CNC Lathe Training

Computer numerical control (CNC) machining can make certain manufacturing processes easier by automating complex commands and speeding up the rate at which equipment completes tasks. But operating a CNC machine is by no means a self-explanatory procedure, and technicians must undergo training to develop the skills necessary for proper CNC handling.

A lathe is a complex machine that presents its own set of challenges, but with the addition of computer numerical controls, the skilled lathe operator must also understand programming parameters, automation-specific safety standards, and a host of other vital pieces of information. It should be emphasized that the completion of a set amount of coursework and the obtainment of appropriate certification are requisite for handling a CNC lathe. Learning about the various types of skills and training that are available may help a prospective technician to plan for an education in CNC machining.

The Learning Curve

An accredited industrial training organization can provide the necessary training for a CNC lathe operator. Most programs will involve multiple classes or sessions, offering a gradual instruction process broken up into several steps. While the beginning stages might not include hands-on experience, later courses typically involve actual lathe operation. In addition, the importance of adhering to safety protocols is reinforced throughout the training process. The following is a typical CNC lathe training outline that may be helpful for illustrating what a student can expect to learn.

Beginners’ Classes

An important training step involves explaining the limitations of computer numerical controls to those who are unfamiliar with its workings. Despite being an automated system, a CNC lathe requires much more than design input to accomplish its task. The technician usually needs to consider tool selection, spindle speed, workpiece clamping and positioning, and cutting sequences before machining can begin. Furthermore, the CNC lathe only understands commands in a specific programming language, such as g-code. CAD specifications must be translated through CAM software in order to be intelligible to a CNC machine. Due to these complex requirements, it is best not to rush through the training program, but to segment the knowledge into learnable chunks. Thus, some early stage coursework might include:

Checking to make sure the lathe is lubricated and learning to schedule routine maintenance in accordance with workplace standards.

Learning to translate product specificationsand work instructions into a machine-readable format.

Establishing criteria for tool selection with efficiency and safety in mind. Installing workpiece handling devices and inserting tools into their corresponding slots.

Learning to load a machining program into the CNC lathe and aligning its data points according to project requirements.

Producing sample parts to verify if they match specifications and operator instructions.

Advanced Classes

After a trainee learns the methods for preparing a CNC lathe for operation and setting its equipment for test runs, the coursework begins to focus on more sophisticated tasks. The initial stages will have taught a technician how to read, comprehend, and create computer numerical control programs. This range of programming instructions typically includes drilling, grooving, facing, threading, and turning. Late stage training will often cover CNC program editing, machine adjustments, and developing new command syntax. Some typical coursework might include:

Identifying editing needs by comparing test results with design specifications and machine instructions. Learning to perform programming edits and updating them in accordance with workplace standards. Producing additional cycles of sample components to verify editing changes and refine the editing process. Regulating and adjusting coolant flow to react to machine and project needs. Taking steps to prevent damage to tools, materials, or machinery during the production cycle. Repairing or replacing tools that have been damaged during operations. Cleaning the lathe and removing any waste material in a safe manner.

Although these guidelines are a broad indication of some of the subjects covered in CNC training, the fundamental principles of following careful instructions, learning safety protocols, and remaining realistic about the capabilities of a CNC lathe will likely be a part of any training curriculum.

Getting an Education in CNC

Getting an Education in CNC

Computer numerical control (CNC) machining can make certain manufacturing processes easier by automating complex commands and speeding up the rate at which equipment completes tasks. But operating a CNC machine is by no means a self-explanatory procedure, and technicians must undergo training to develop the skills necessary for proper CNC handling.

A lathe is a complex machine that presents its own set of challenges, but with the addition of computer numerical controls, the skilled lathe operator must also understand programming parameters, automation-specific safety standards, and a host of other vital pieces of information. It should be emphasized that the completion of a set amount of coursework and the obtainment of appropriate certification are requisite for handling a CNC lathe. Learning about the various types of skills and training that are available may help a prospective technician to plan for an education in CNC machining.

The Learning Curve

Although there are many technical schools out there, an accredited industrial training organization can provide the necessary training for a CNC lathe operator. Most programs will involve multiple classes or sessions, offering a gradual instruction process broken up into several steps. While the beginning stages might not include hands-on experience, later courses typically involve actual lathe operation. In addition, the importance of adhering to safety protocols is reinforced throughout the training process. The following is a typical CNC lathe training outline that may be helpful for illustrating what a student can expect to learn. Beginners’ Classes

An important training step involves explaining the limitations of computer numerical controls to those who are unfamiliar with its workings. Despite being an automated system, a CNC lathe requires much more than design input to accomplish its task. The technician usually needs to consider tool selection, spindle speed, workpiece clamping and positioning, and cutting sequences before machining can begin. Furthermore, the CNC lathe only understands commands in a specific programming language, such as g-code. CAD specifications must be translated through CAM software in order to be intelligible to a CNC machine. Due to these complex requirements, it is best not to rush through the training program, but to segment the knowledge into learnable chunks. Thus, some early stage coursework might include:

Checking to make sure the lathe is lubricated and learning to schedule routine maintenance in accordance with workplace standards.

Learning to translate product specificationsand work instructions into a machine-readable format.

Establishing criteria for tool selection with efficiency and safety in mind. Installing workpiece handling devices and inserting tools into their corresponding slots.

Learning to load a machining program into the CNC lathe and aligning its data points according to project requirements.

Producing sample parts to verify if they match specifications and operator instructions.

Advanced Classes

After a trainee learns the methods for preparing a CNC lathe for operation and setting its equipment for test runs, the coursework begins to focus on more sophisticated tasks. The initial stages will have taught a technician how to read, comprehend, and create computer numerical control programs. This range of programming instructions typically includes drilling, grooving, facing, threading, and turning. Late stage training will often cover CNC program editing, machine adjustments, and developing new command syntax. Some typical coursework might include:

Identifying editing needs by comparing test results with design specifications and machine instructions.

Learning to perform programming edits and updating them in accordance with workplace standards.

Producing additional cycles of sample components to verify editing changes and refine the editing process.

Regulating and adjusting coolant flow to react to machine and project needs. Taking steps to prevent damage to tools, materials, or machinery during the production cycle.

Repairing or replacing tools that have been damaged during operations. C leaning the lathe and removing any waste material in a safe manner.

Although these guidelines are a broad indication of some of the subjects covered in CNC training, the fundamental principles of following careful instructions, learning safety protocols, and remaining realistic about the capabilities of a CNC lathe will likely be a part of any training curriculum.

How To Become a Welder

Welders work in a variety of industries, joining metals together with heat. Welders can work on many kinds of structures, such as mobile homes, pipes, steel reinforcement and others, because welding is a relatively easy manufacturing process and provides a great deal of strength.

According to the U.S. Bureau of Labor, welding has a good forecast for growth over the 2006-16 decade, which is slightly lower than average of all jobs at five percent. Also, as the oil market grows, demand for welder grows as well. Welding isn’t threatened much by technological advances because of its reliance on human oversight, and the fact that automated welding simply cannot perform many projects. Depending on the industry, the level of training and other factors, welders generally make between $30-50,000 a year.

There are a few different ways to become a welder in the United States. Special certification is not required in many states, but a welder’s background can be important to prospective employers, and certification is available at special welding and vocational schools. These schools offer many different programs for different welding techniques. On-the-job training is also available in the form of apprenticeships. Specialty Welding and Vocational Schools

There are many welding schools available across the country. The American Welding Society has a school locator and links to many welding competitions for welders-in-training. Looking at brochures and reading school reviews is very helpful for a prospective student to determine if the program is right for him or

Welding schools can last a matter of weeks to months. Classes are designed to appeal to a wide range of applicants, so schools usually offer both day and evening sessions for students to work around their other schedules. Competitive school programs will provide students with adequate welding bays for hands-on learning, and courses will be taught by certified teachers, either former industry professionals or professional welding teachers. Additionally, class sizes are often small enough to get individual attention.

Many schools offer a lot of different training tracks, from general structural classes to more advanced, master welder courses. The more advanced classes will generally cost more money. Welding schools can cost in the couple-thousand dollar range, but most all of them assist students in obtaining some financial aid, usually in the form of a loan. Some schools will even assist students in obtaining lodging for the duration of the coursework.

One major draw to a welding class is the job placement assistance offered to students. Not only do students get hands on, professional training, but schools will typically host business visits so companies can recruit new welders from the student body. Even though the welding industry has very good employment rates, having this kind of help can make finding a job and starting a career that much easier for a beginning welder.

Not all states require professional welders to be certified, but certification can certainly help make a welder attractive to prospective employers and customers. Look into your state’s certification requirements or ask for information at the welding school. Most schools have certification programs in addition to the general classes. On-the-Job Training

Employers are eager for new talent, but are also eager to retain this talent. If an investment into the training of an inexperienced welder is going to pay off in a long term relationship between the employee and the company, then the hiring agent is going to be more interested in employing the prospective welder. This is why many companies host apprentice programs. These programs provide on-the-job training for prospective welders, while usually supplying some type of stipend. This occurs under a specific agreement, signed by both parties, about the length and scope of the training, as well as the aim of the trainee to remain with the company for a specific amount of time. Other methods

Other methods of welding training require a bit of luck and foresight. Those who start lucky can begin learning welding in high school shop class, although funding for these classes is dropping nationwide and their availability is location specific. Additionally, some people may have a relative or friend who is a professional or hobby welder.

If a hopeful welder does not have access to any of the above opportunities, he or she might look into local community colleges, which sometimes have welding classes available very cheaply. Sometimes businesses will run classes through a community college as a way of outreach and a way of scouting for talent.

Application Of Precision Stampings

Precision stamping is a fast and cost-effective solution for manufacturing large quantities of complex products. There are three major precision stamping applications currently in use at factories across the globe: micro-precision stamping, intricate precision metalwork, and prototype design.

Metal stamping uses high tonnage presses and stamping dies to forge sheets of metal into complete or semi-complete parts. Precision metal stamping improves the speed and accuracy of complex stamping applications by allowing the stamping, folding, drawing, or piercing of a product in a single or series operations.

Benefits and Disadvantages Of Precision Stamping

Precision stamping can be highly automated, making the process well-suited for high-volume because labor costs drop as production levels increase. Upfront tooling costs, however, may render precision stamping ineffective for smaller production runs. Other factors to consider include long lead times and difficulty making design changes once the tools have been created.

What Is Micro Precision Metal Stamping?

Micro-precision stamping is capable of making minute stamps, cuts, bends, and folds in a workpiece. Typically, micro-precision stamping machines support tools with diameters on the micron level. Minimum diameter capabilities vary depending on the particular machine, but .002 inches and .005 inches are common minimum specifications. These micro-stamping combine photo etching technology and 3D computer software to perform highly exact operations.

Benefits of Micro Precision Thin Material

Aside from its effectiveness in manufacturing small parts, precision micro-stamping provides numerous other advantages. Some of these include:

Reduced risk: The inclusion of modular and digital tooling reduces tooling costs. Quick results: Thanks to decreased tooling barriers, production can be finished within days. Improved flexibility: Changes in product designs are less costly or time consuming than with traditional precision stamping methods.

Intricate Precision Metal Work

Complex products or innovative designs sometimes require a more sophisticated precision stamping procedure. When this is the case, manufacturers often seek out a stamping company that specializes in complex or intricate precision metalwork. These companies will have the considerable experience and advanced technologies necessary for fabricating products with intricate geometries, cuts, folds, or engravings with exact specifications. Some of the technologies that make intricate precision metal working possible include:

In-die extrusion and tapping: Extrusion and tapping are both performed in the same die to eliminate the need for a weld nut Progressive die design: This method applies sophisticated software to improve the die development. Deep draw stampings: Deep drawing allows the formation of 3D shapes, such as squares, cylinders, and shells. Transfer stamping: This technique reduces costs and secondary operations when stamping complex geometries. Class A dies: These dies deliver increased accuracy over steel rule dies. Magnified optical devices: Magnified optical devices provide more precise grinding results.

Applications of Intricate Precision Metal Work

Many industries require that produce complex components may benefit from intricate precision metal stamping. Some products routinely fabricated with the help of complex precision stamping techniques include:

Automotive engines Aircraft components Machine gears Complex electronics Telecommunication products

Prototype Design and Precision Stamping

Many precision stamping companies offer prototype design service without the need for expensive dedicated tooling. This helps make prototype design and production cost-effective prior to committing to a final design. Computer programming the stamping equipment also improves the turnaround time. While traditional techniques may take days or weeks to manufacture upfront tooling devices, a company that specializes in prototype design can often deliver same-day or next-day results.

Types of Prototype Design

Prototypes are manufactured through two main processes: single-part transfer and progressive strip prototyping. These processes entail:

Single-part transfer prototyping: In this process, individual prototype parts are manually moved from station to station. At each station, the part is blanked or metal formed. The main advantage of this method is reduced tooling costs at warehouses that maintain a standard system for design. The disadvantages of single-part transfer include high parts costs and the inability to incorporate miniature parts or complex feature tolerances.

Progressive strip prototyping: This method differs from single-part transfer in that a progressive die guides the contained stock prototype material through each step in the design process. At each station, the die completes an operation and delivers a complete product at the final stage. Movement of the die along the strip is either manual or controlled by an automatic feeder. Due to increased automation, progressive strip prototyping is good for applications that require miniature part sizes, advanced feature tolerance, and improved production speed.

Die Casting Process Types

Die casting is a popular manufacturing process for casting metal products. There are two main die casting process types and several variations in process design. When molten metal is forced into mold cavities at high pressure, it is known as die casting. The process is best suited for speedy production of bulk metallic parts that require minimal post-production machining. The main benefits of the die casting process include:

High quality: Parts created through die casting deliver a long service life. High reliability: Uniformity of mass-produced parts is exceptional. Quick production: Die cast tooling requires minimal maintenance. Versatile design: Die casting can createvirtually any size, part geometry, surface texture or luster.

Minimal assembly: Assembly features such as studs, drill holes and bosses can be integrated into mold design.

Applications of Die Casting Processes

Die casting is a process that has far-reaching applications. Any part production process that creates high-volume metal components will likely benefit from die casting. A variety of manufacturing industries currently rely on one or many types of die casting processes, including the auto, aerospace and power tools industries. Types of Die Casting Processes

All die casting process types are designed with the same goal in mind—cast a mold using injected molten metal. Depending on the type of melted metal, part geometry and part size, different die casting processes can deliver superior results over alternative methods. The two main types of die casting processes are hot-chamber and cold-chamber die casting. Variations on these two types of die casting include:

Low-pressure die casting Vacuum die casting Squeeze die casting Semi-solid die casting

The Hot-Chamber Die Casting Process

Hot-chamber die casting, sometimes called gooseneck casting, is the more popular of the two die casting processes. In this process, the cylinder chamber of the injection mechanism is completely immersed in the molten metal bath. A gooseneck metal feed system draws the molten metal into the die cavity.

While direct immersion in the molten bath allows for quick and convenient mold injection, it also results in increased corrosion susceptibility. Due to this fact, the hot-chamber die casting process is best suited for applications that utilize metals with low melting points and high fluidity. Good metals for the hot-chamber die casting process include lead, magnesium, zinc and copper. The Cold-Chamber Die Casting Process

The cold-chamber die casting process is very similar to hot-chamber die casting. With a design that focuses on minimizing machine corrosion rather than production efficiency, the melted metal is automatically- or hand-ladled into the injection system. This eliminates the necessity for the injection mechanism to be immersed in the molten metal bath.

For applications that are too corrosive for the immersion design of hot-chamber die casting, the cold-chamber process can be an excellent alternative. These applications include the casting of metals with high melting temperatures, such as aluminum and aluminum alloys.

The Low-Pressure Die Casting Process

Low-pressure die casting is a process best suited for aluminum components that are symmetric around an axis of rotation. Vehicle wheels, for example, are often fabricated through low-pressure die casting. In this type of process, the mold is situated vertically above the molten metal bath and connected via a riser tube. When the chamber is pressurized (usually between 20 and 100kPa), the metal is pulled upward and into the mold. The elimination of feeders from this type of die casting process delivers the high casting yields. The Vacuum Die Casting Process

Vacuum pressure casting (VPC) is a relatively new die casting process that delivers enhanced strength and minimal porosity. This process is similar to low-pressure die casting, except the locations of the die cast mold and molten metal bath are reversed. The cylinder chamber can become a vacuum, which forces the molten metal into the mold cavity. This design reduces turbulence and limits the amount of gas inclusions. Vacuum die casting is especially beneficial in applications destined for post-casting heat treatment. The Squeeze Die Casting Process

Squeeze casting was created as a workable solution for casting metals and alloys with low fluidity. In this process, the molten metal fills up an open die, which then squeezes closed, forcing the metal into the recessed portions of the molding. The squeeze casting process delivers extremely dense products and is a complementary process to subsequent heat-treating. The process is most often associated with molten aluminum, and is used in applications that call for fiber reinforcement. The Semi-Solid Die Casting Process

Semi-solid die casting, sometimes called Thixoforming, is another process that delivers minimal porosity and maximum density. A machine cuts the workpiece into smaller slugs, and then heated. Once the metal has reached the phase transition between solid and liquid, resulting in a somewhat slushy texture, a shot sleeve forces it into the mold cavity, where it hardens. The benefit of this is improved precision. Non-ferrous metals such as magnesium alloy and aluminum alloy are most often used with the semi-solid die casting process.

How Die Casting Alloys Work

How Die Casting Alloys Work Die-casting is a fabrication technique involving high pressure injections of liquefied metal into a cast. It is useful for accurately mass-producing items according to specifications. Many products, such as automobile parts, sink faucets, and connector housings, are created using the process.

Die-casting can be an appealing and cost-effective method for manufacturing sturdy items. When selecting an appropriate fabrication material, there are several factors to consider, including the type of die-casting process to be used and the intended function of the product.

Types of Die-Cast Processes

Two common die-casting methods are the cold-chamber and hot-chamber processes, and distinguishing the proper method largely depends on the size of the finished product and the alloy selected. For example, aluminum is a more efficient choice for the cold-chamber process than it is for the hot-chamber method.

Cold-Chamber Process: Metal is liquefied in a furnace, then ladled into a cold chamber. This technique is often used with metals that alloy quickly with iron at high temperatures, such as copper and aluminum, because these materials would regularly pose problems when melted in a (part-iron) casting machine. The cold-chamber process is better-suited to metals with high melting points.

Hot-Chamber Process: Metal is melted in the casting machine, and fed into the die. The injection method allows metal to be added more quickly, but is ineffective with materials that have high-melting points, such as aluminum-based alloys. Therefore, a hot-chamber process is typically used with tin, lead, or zinc-based alloys. Types of Alloys Used in Die-Castings

Aluminum is commonly employed in die-casting, but is prone to cracking or shrinking at high temperatures, so it is often alloyed with copper or silicon. Combining aluminum with these metals greatly increases its hardiness and fluidity. Since it has high dimensional stability, aluminum is used to create components with thin walls and complex shapes. Due to its corrosion resistance, aluminum is also beneficial in components that will face exposure to thermal or electrical energy.

Copper-based alloys are also commonly employed in die-casting. Many of these alloys are quite durable, making them an effective choice for mechanical products. Due to copper’s very high resistance to corrosion, it is often used to create plumbing and electrical material.

Zinc is relatively easy to cast and maintains high strength at room temperature, but can be alloyed with aluminum to further improve these qualities. Zinc has a lower melting point than aluminum and is suitable for hot-chamber casting. It is also valuable in the manufacture of products that require high precision and sturdiness, such as connectors and gears.

Magnesium has a high strength-to-weight ratio despite being a relatively light alloy, and it is useful for die-casting operations that require thin-structured walls and close precision.

Considerations When Choosing Die-Casting Alloys

The function and use of the final product will dictate die-casting alloy selection. For example, if the component requires high strength and corrosion resistance, an aluminum or copper based alloy could be an effective choice. Another consideration is production volume. With proper maintenance, aluminum die-casts can have a life of approximately 100,000 cycles, while zinc molds can last up to one million cycles before being replaced. For long-term, high-volume production, it may be more cost-effective to use alloys that maximize the life of the molds. When considering various fabrication methods, it may be helpful to examine the advantages and disadvantages of using a die-casting process.

Potential advantages include:

Dimensional Strength: die-cast parts are stronger than plastic components.

Rapid Production: die-cast components can be produced in high volume with relatively little tooling or machining.

Smooth Surfaces: the die-cast process can create finished parts with curved or seamless surfaces.

Accuracy: die-cast parts can be created with close adherence to specifications.

Possible disadvantages include:

High Volume: smaller production runs may reduce cost-effectiveness.

Limited Metal Fluidity: alloy malleability varies, which can limit the complexity and shape of the finished product.

Size and Weight Limits -- A casting machine’s capacity limits the range of product dimensions.

Related Products and Categories Die-casting is used for a variety of consumer, commercial and industrial manufacturing purposes, such as the production of automobile powertrains, engine parts, telecommunications equipment, marine equipment, household appliance parts and hand tools.

There are numerous variants within the die-casting process. Some of the related materials and procedures include:

Single-cavity die: A mold designed to create a single component.

Multiple-cavity die: A mold designed to create several identical parts.

Unit die: A mold designed to create several different parts that are all part of the same component.

Die lubricant: Liquid applied to the interior surfaces of the mold to ensure easy removal of the component.

How to Design a Die Casting Mold

Die casting is a technique for mass-producing metal products and components. Mold design is one of the most important steps in the process because the shape and attributes of the mold will directly affect the final product. The die casting procedure forces molten metal into molds using high pressure and it requires a mold with exact specifications to achieve the task.

The Importance of Mold Design

Mold design affects the shape, configuration, quality, and uniformity of a product created through the die casting procedure. Improper specifications can result in tool or material corrosion, as well as inferior product quality, while an effective design can improve efficiency and production time.

Factors Contributing to Quality Mold Design

There are a number of mold design factors to consider when deciding on the appropriate specifications for a project. Some of these factors include:

Die draft Fillets Parting lines Bosses Ribs Holes and windows Symbols Wall thickness

Draft

Draft is the degree to which a mold core can be tapered. A precise draft is needed to smoothly eject the casting from the die, but since draft is not constant and varies according to the angle of the wall, features such as the type of molten alloy used, shape of the wall, and depth of the mold can affect the process. Mold geometry can also influence draft. In general, untapped holes require tapering, due to the risk of shrinkage. Likewise, inner walls can also shrink, and therefore require more drafting than outer walls.

Fillets

A fillet is a concave junction used to smooth an angled surface. Sharp corners can hinder the casting process, so many molds have fillets to create rounded edges and reduce the risk of production errors. With the exception of the parting line, fillets can be added nearly anywhere on a mold.

Parting Line

The parting line, or parting surface, connects different sections of the mold together. If the parting line is imprecisely positioned or becomes deformed from work strain, material may seep through the gap between the mold pieces, leading to non-uniform molding and excessive seaming.

Bosses

Bosses are die cast knobs that serve as mounting points or stand-offs in mold design. Manufacturers often add a hole to the interior structure of the boss to ensure uniform wall thickness in a molded product. Metal tends to have difficulty filling deep bosses, so filleting and ribbing may be necessary to alleviate this problem.

Ribs

Die cast ribs can be used to improve material strength in products lacking the wall thickness required for certain applications. Selective rib placement can reduce the chance of stress cracking and non-uniform thickness. It is also beneficial for decreasing product weight and improving fill capabilities.

Holes and Windows

Including holes or windows in a die cast mold directly affects the ease of ejecting a completed molding and enables the creation of substantial drafts. Additional features, such as overflows, flashovers, and cross feeders may be necessary to prevent unwanted casting within the holes or poor material flow around the holes.

Symbols

Manufacturers often include brand names or product logos in the mold design of die-cast products. While symbols do not typically complicate the die casting process, their use can affect production costs. In particular, a raised logo or symbol requires additional molten metal volume for each manufactured part. Conversely, a recessed symbol requires less raw material and can reduce expenses.

Stainless Steel Fabricating Processes

Due to its versatility, there are a wide range of stainless steel fabricating techniques. It may be helpful to review some of the processes involved in order to better understand the benefits and disadvantages of the different types of stainless steel fabrication.

Although it has relatively high strength and work hardening rates, stainless steel is malleable enough to be bent, folded, machined, welded, deep drawn, or spun. This guide will focus on three common stainless steel fabricating processes: work hardening, machining, and welding. Work Hardening with Stainless Steel

Work hardening is the process of strengthening material through deformation. Relative to other varieties of steel, stainless steel work hardens quickly, although the exact rate depends on the specific grade of the alloy. The austenitic family of stainless steel, for example, has a hardening rate slightly higher than that of carbon steel and is a frequently used grade series in fabrication processes.

It is also helpful to match the steel grade with a work hardening treatment that is well-suited for it. Since austenitic stainless steel can usually be hardened only through cold working, a thermal treatment process would be better applied to other grades, such as those in the martensitic family. Work Hardening Rates of Stainless Steel

Since ferritic stainless steels yield lower work hardening rates, austenitic and martensitic stainless steels are the series that benefit most from work hardening applications. In some instances, austenitic stainless steel can be cold worked up to 1,000 MPa, although the maximum is typically in the 800 MPa range. When cold drawn, stainless steel may reach tensile properties of 2,000 MPa or greater, but such high strength levels are usually limited to fine wire sizes. Size is a concern due in part to the quick work hardening rate of stainless steel, which yields diminishing tensile strengthening at the core of a wire as its diameter increases.

A fast work hardening rate provides certain benefits, as well. For example, stainless steel’s hardening rate renders the alloy effective in projects that require high strength and corrosion resistance. Common applications include the manufacturing of nuts and bolts, machine parts, cryogenic machinery and hospital equipment. The martensitic group, in particular, displays the highest levels of hardness and corrosion resistance among the stainless steel categories, making it a popular alloy for the production of tools, valve parts, bearings, and cutlery. Other Characteristics of Stainless Steel

Work hardening can also increase the magnetism of stainless steel. While its magnetism tends to be relatively slight, grades with higher work hardening rates exhibit higher levels of magnetic capacity after treatment. Stainless steel also undergoes greater deformation at slower forming speeds, requiring some high-speed forming processes to be slowed down to improve their work hardening efficiency. Machining Stainless Steel

Grades 303, 430, 410 and 416 achieve resistance to chipping when alloyed with manganese sulfide. Due to the decreased ductility and corrosion resistance that comes with the addition of manganese sulfide, these grades have limited machining applications, though several free-machining grades have been developed to address the problem.

To overcome the limits of machining certain types of stainless steel, some companies have incorporated exclusive steel melting techniques to improve the machinability of commonly-used austenitic grades. These specialized processes can improve machining efficiency, and may contribute to longer tool life. Tips on How to Machine Stainless Steel

Due to several concerns, such as the possibility for chipping, machining stainless steel can be a complex process. Here are some suggestions that may help with machining this alloy:

Apply coolants or lubricants to the equipment Use large tools to help dissipate heat Maintain light cuts and constant feeds Use chip breakers to deflect debris Select a machine tool that reduces vibration Keep the cutting edge sharp at all times

Welding Stainless Steel

Most types of stainless steel can be welded, but the degree of efficiency depends on the grade. Here are some tips for welding each category of stainless steel:

Austenitic: most grades of the austenitic family, except for free-machining Grade 303, are well-suited for welding purposes. However, this group is susceptible to sensitization and inter-granular corrosion on thicker products. For projects that involve welding thick materials, it may be better to use low carbon content grades such as 304L or 316L. Some stabilized grades, such as Grade 347, may also be effective.

Martensitic: these grades are also good options for welding, but may be prone to cracking. To help reduce the likelihood of fractures, pre-heat and post-heat the material, or use supplementary austenitic filler rods.

Ferritic stainless steel: though relatively less suitable for welding, some stabilized ferritic grades, such as Grade 409, may be appropriate for certain projects. Issues such as sensitization, low ductility, and high grain growth may be overcome with the help of austenitic stainless steel fillers or by post-heating the welded material.

Duplex: this set of grades works well for low thermal expansion and is welding efficient. Some suitable welding grades such as Grade 2205, have higher nickel content to improve ductility, strength, and corrosion resistance.

Alloys Used Die Casting

As a fabrication process, die casting is notable for its capacity to manufacture parts with a high degree of uniformity, close design accuracy, and quality surface finishes. In many cases, die casting can reduce or eliminate the need for post-production machining, raising the cost-efficiency of the process and shortening fabrication time. While it may be difficult to die cast sturdier metals, such as certain grades of steel, there are many other types of alloys well-suited for die casting methods.

Die casting molds are usually constructed from hardened steel and they are often the most expensive component in a die casting machine. These molds can handle a range of different alloy families with varying results, but die casting is generally most effective on metals with low fusing temperatures. For this reason, the common die casting alloys fall into a handful of categories based on their composition and material properties.

Zinc Alloys

Zinc-based materials are relatively easy to die cast, and respond well to the die molding process. These materials are comprised of multiple metals in specific ratios. For example, a typical zinc-based die casting workpiece consists of 86 percent zinc, 4 to 7 percent copper, and 7 to 10 percent tin. Slightly higher proportions of tin make the workpiece more flexible, while increased copper levels improve rigidity. Zinc alloys have a melting point in the range of 700 to 800 degreees Fahrenheit.

Zinc alloys are often used in place of cast iron or brass, but tend to have lower tensile strength than their sturdier counterparts. Unless it is specially reinforced during the alloying process, zinc-based material cannot exceed approximately 17,000 pounds per square inch of force. As a result, die cast zinc products are generally not used in applications involving high mechanical loads. Zinc castings can also be corroded by alkaline substances or salt-water, and are often plated to preserve their luster despite atmospheric conditions.

Tin Alloys

Alloys composed with a significant amount of tin as a base metal are most often used in applications requiring corrosion resistance, such as those involving the food industry or internal and external bearings. While the proportion of metals in these alloys can vary widely, a typical tin alloy consists of 90 percent tin, 6 percent antimony, and 4 percent copper, which is added to strengthen the material’s durability. Tin alloy die castings generally weigh under ten pounds and rarely exceed 1/32 of an inch in thickness. They are valued for their resistance to alkaline, acids, and water, but feature a comparatively low tensile strength rating of below 8,000 pounds per square inch. Bronze and Brass Alloys Most bronze and brass materials can be die cast as effectively as zinc-based alloys, although small holes can only be drilled into the workpiece after casting, rather than during the casting process. Bronze and brass are commonly used to create washers, camshaft components, and decorative products (due to their distinctive coloring and potential for surface finishes). A typical brass alloy consists of 60 percent copper, 40 percent zinc, and 2 percent aluminum, but there are many variations on this mixture. Die casting bronze and brass is capable of yielding products with a durable surface and highly accurate interior specifications.

Some brasses have difficulty tolerating shrinkage from high temperature processes, but despite these challenges, most of these alloys can be used for products weighing up to fifteen pounds and with thicknesses at or under 1/32 of an inch. They are generally suitable for applications requiring tensile strength of less than 8000 pounds per square inch.

Aluminum Alloys

Die cast aluminum alloys are often found in automobile parts and gears, and have been used to create surgical instruments in the past. They are generally stronger and lighter than most zinc-based materials, but tend to be more expensive to create. Using aluminum alloys can reduce the need for finishing treatments, such as plating, and a common grade is composed of 92 percent aluminum mixed with 8 percent copper. Magnesium may be added to this alloy to improve its tensile strength from around 21,000 pounds per square inch to approximately 32,000 per square inch, while nickel can be included to increase rigidity and provide a higher surface finish. The melting point for an aluminum alloy is around 1150 degrees Fahrenheit.

Lead Alloys

Like tin alloys, lead-based materials tend to be used for their corrosion resistance and in applications requiring no more than 8000 pounds of tensile strength per square inch. Common applications include fire-safety equipment, bearings, and various decorative metal goods. They are relatively inexpensive for producing castings under 15 pounds, but lead alloys cannot be used for products that will be in contact with food. A typical lead alloy might be 90 percent lead and 10 percent antimony, with tin being a common addition as well. The melting point is usually around 600 degrees Fahrenheit, and product thickness rarely exceeds 1/32 of an inch.

For insight on the history of die casting procedures and the scientific principles underpinning them, please see Die-Casting, by Edmund Francis Lake and Chester L. Lucas.

Aluminium Extrusion in Construction

Aluminum extrusion has become an important feature in construction because of its cost benefits and structural integrity. Additionally, aluminum is prized for adding metal accents to glass surfaces. Because aluminum extrusion allows for complex shapes on long continuous pieces, it can be exploited for numerous different construction materials.

The Extrusion Process

Extrusion is a process of shaping different molten materials, like metals or plastic, by forcing them through shaped designs at high pressures. Because of the process’s flexibility, there are a number of methods for performing it, including hot or cold, and continuous or semi-continuous.

A really simple analogy for extrusion would be a pasta machine. The prepared dough is sent through a press, which emits long, continuous strands of spaghetti. Metal extrusion is very similar, except on much larger scale. A mostly automated process involves workers melting down a metal to its molten form, then transferring it to the extrusion machine. The extrusion machine then forces the molten metal, by way of either hydraulic or mechanical power, through a steel die at high pressure. If it’s a continuous extruder, the press will continue to force the metal in one long, continuous section until the piece is done. If it’s semi-continuous, the press will cut off the pieces one by one as the metal is forced through the die. The finished pieces are then transported further down the assembly line for cleaning and finishing.

Costs for extrusion are limited to die molding, materials and manpower. Because an extrusion press can be outfitted with different dies, a manufacturer investing in the press will see longterm use. Steel dies vary in price but can be expensive for more intricate, precision varieties. With aluminum extrusion, the customer is fortunate to be using a relatively inexpensive metal that also has desirable strength capabilities. Although not on the level of a case-hardened steel, aluminum’s structural integrity is quite robust while remaining light, which is why it sees use in aerospace and construction applications.

Extruded Aluminum in Construction

Extruded aluminum products are versatile, both in application and production. Manufacturing extruded aluminum can be done by either cold or hot processes, continuously or semi-continuously. Lightweight extruded aluminum paneling or guide rails are common for trailer, shed and furniture construction, but denser aluminum structures are becoming common.

Recent construction in Chicago has employed over a million tons of extruded aluminum parts. Architects of recent high profile projects going up in “The Loop,” the Second City’s famed business district, have spoken of consciously trying to fit their buildings into Chicago’s Art Deco style, while retaining a contemporary feel. An executive V.P. at Lohan Caprile Goettsch Architects said that extruded aluminum was a “perfect choice,” to maintain this classic feel, while also serving utilitarian ends. “The extruded profiles are thermally improved, so heat doesn’t transmit through the curtainwall system,” he said.

Extruded aluminum is not just limited to exterior design and function, either. Lighting fixtures, elevator shafts and stairwells all employ many different applications. While aluminum can’t make up the basic frame skeleton of a building, it accents and aids the structure in the interior. Integrated extruded aluminum design features in almost all areas of building construction, including structural mechanical, plumbing and others.

Additional bonuses to using extruded aluminum are the reusability and recyclability of the material. It is a product that is fairly easy to re-appropriate or to refashion into another use, or properly melt down and completely recycle. This makes it additionally desirable to environmentally-conscious architects and manufacturers.

References:

Aluminum Extrusion Showcase, “High-Rise building the Green Way is Transforming Chicago’s Skyline.”http://www.aec.org/exapps/greenbuildingdesign.html"