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Making Sense of Aluminum Extrusion Tempers

Aluminum BilletsWhen considering the use of extruded aluminum to solve a design problem, you should be familiar with aluminum alloys and tempers. Aluminum alloys are identified primarily by a series number— a four-digit code describing its metallurgical composition. For extruded aluminum, the most common series are 6000’s and 7000’s.

The 6000 (Al-Mg-Si) series is the most popular alloy given that it doesn’t work-harden quickly. This means it can be more easily extruded and profiles manufactured more cost-effectively. The 7000 series has a significant amount of zinc which makes it the strongest alloy and popular for marine, automotive and aviation applications, but takes higher forces to extrude.

While the alloys themselves do offer certain levels of strength, based on the secondary mineral or compound added to the aluminum, that alone should not be the basis for selecting one over another. Depending on the composition of your alloy, aluminum can be further strengthened and hardened using quenching (cooling), heat treatment, and/or cold working techniques. This is called the temper and appears as a hyphenated suffix to the basic alloy number, such as 6061-T1.

How Tempers Impact Your Product

Each of these techniques can enable designers to achieve desired mechanical properties using a more easily extruded, less expensive alloy. For example, alloy 6063, typically a good match for decorative purposes, offers an attractive surface finish and can be used to extrude thin walls or fine details. Un-heat-treated 6063 has an ultimate strength no more than 19,000 psi and no specified maximum yield strength. At first glance, its use seems limited given its low strength. However, when T6 tempered (6063-T6) its minimum ultimate strength becomes 30,000 psi and its minimum yield 25,000 psi. This increase in strength created with a combination of solution heat treatment and artificial aging makes the alloy useful for architectural applications, particularly window and door frames.

The temper of each alloy can also create considerable variances in their characteristics and how they react to various fabrication processes, such as punching, forming and welding. Understanding these designations ensures you don’t destroy key capabilities. For example, you can improve the corrosion resistance of certain alloys by choosing an appropriate solution heat treatment, a suitable quench rate, and age-process sequence, at the expense of strength. And vice versa.

Basic Temper Designations

The first designation, which is a letter (F, H, O, T or W), indicates the general class of treatment. The first digit after the letter indicates a basic operation. For example, 6060-T4 indicates the use of 6060 alloy and a T4 temper, which means the extrusion is thermally treated (T) after being extruded and then naturally aged (4).

F As fabricated – Applies to products of a forming process in which no special control over thermal or strain hardening conditions is employed
O Annealed – Applies to a product which has been heated to produce the lowest strength condition to improve ductility and dimensional stability
H Strain Hardened – Applies to products which are strengthened through cold-working. The strain hardening may be followed by supplementary thermal treatment, which produces some reduction in strength. The “H” is always followed by two or more digits.
W Solution Heat-Treated – An unstable temper applicable only to alloys which age spontaneously at room temperature after solution heat-treatment
T Thermally Treated – To produce stable tempers other than F, O, or H. Applies to a product which has been heat-treated, sometimes with supplementary strain-hardening, to produce a stable temper. The “T” is always followed by one or more digits.

Further to the basic temper designation, there are two subdivision categories to the “H” Temper (Strain Hardened) and “T” Temper (Thermally Treated) categories.

Subdivisions of H Temper – Strain Hardened

The first digit after the H indicates a basic operation: The second digit after the H indicates the degree of strain hardening:
H1 – Strain Hardened Only HX2 – Quarter Hard
H2 – Strain Hardened and Partially Annealed HX4 – Half Hard
H3 – Strain Hardened and Stabilized HX6 – Three-Quarters Hard
H4 – Strain Hardened and Lacquered or Painted HX8 – Full Hard
HX9 – Extra Hard

Subdivisions of T Temper – Thermally Treated

The first digit after the T indicates a basic operation:
T1 – Naturally aged after cooling from an elevated temperature shaping process, such as extruding.
T2 – Cold-worked after cooling from an elevated temperature shaping process and then naturally aged.
T3 – Solution heat-treated, cold-worked and naturally aged.
T4 – Solution heat-treated and naturally aged.
T5 – Artificially aged after cooling from an elevated temperature shaping process.
T6 – Solution heat-treated and artificially aged.
T7 – Solution heat-treated and stabilized (overaged).
T8 – Solution heat-treated, cold-worked and artificially aged.
T9 – Solution heat-treated, artificially aged and cold-worked.
T10 – Cold-worked after cooling from an elevated temperature shaping process and then artificially aged.
Additional digits after the T indicate stress relief:
TX51 or TXX51 – Stress relieved by stretching.
TX52 or TXX52 – Stress relieved by compressing.

What to know more? Download a complete guide to aluminum extrusion tempers.

Rather than attempt to become an alloy expert, engage your aluminum extrusion manufacturer early in the design process. Discuss the component or product’s end-use and your specific requirements, such as strength, environmental conditions, finish, and fabrication needs, and let the extruder’s engineer make suggestions. These are experts waiting to help you make the best product possible—a valuable resource that every designer should take advantage of.

Disclaimer: This content is provided solely for the purposes of providing information about the aluminum extrusion process and use of aluminum alloys. Vitex does not make any guarantee or promise about how an alloy may perform under the extrusion techniques noted.

Employee Spotlight: Mike Henderson, Director of Materials & Planning

Mike HendersonMike Henderson learned the aluminum extrusion business from the ground up. Having held a variety of positions during his 29 years with Vitex, he has a deep understanding of how all the various processes integrate to make a finished product. As our Director of Materials & Planning, Mike ensures we have the right amount of materials on hand to meet our production requirements. He is also responsible for scheduling all of our customers’ orders throughout the extrusion process.

Q & A with Mike Henderson

Tell us about your history with Vitex and how you came to join the company?

I was interested in the manufacturing industry and applied to several manufacturers after graduating from High School. I accepted a position with Vitex because I felt it offered the best opportunity to build a future for myself and my family—which it has.

I started out as a saw helper, then moved to saw operator, then stretcher operator. I moved up to working on the extrusion press line as a helper, then promoted to Press Operator, and later Press Supervisor.

Running the press was pretty cool, but I knew I didn’t want to do it for the rest of my life so I went to night school for 3 years and volunteered in the front office a couple of hours a day to learn more about the business and prove myself to the company. My persistence paid off when I was offered the Scheduling Coordinator position, then later promoted to Extrusion Manager and then Director of Extrusion Operations.

What do you like best about your job?

Solving problems. Given how long I’ve been with the company, I’m often the “go to” person for help figuring out a problem, which I don’t mind. Usually, with a little research and detective work I can come up with a solution.

What valuable skills are needed for your job?

Organizational skills are critical. There are always so many things happening at the same time; if you aren’t organized you get overwhelmed very quickly. Computer skills and the ability to communicate well are also very important.

What have you learned while working at Vitex?

I’ve learned the importance of teamwork. It may sound like an overused buzzword, but it truly applies at Vitex. We either succeed as a team or we fail as a team, and failure isn’t an option. By working together we achieve our goals.

Tell us something you enjoy about working at Vitex.

The great people—they are one of the reasons I’ve stayed with the company as long as I have. Work can be challenging if you don’t like the people you work with.

Tell us about a favorite project you’ve worked on?

I was the Extrusion Manager when we installed the new press in 2011 and was very involved in the startup of the new line. There were many long days and sleepless nights trying to get productivity up as quickly as possible, but there was an overwhelming sense of accomplishment when we started to hit our targets.

What do you enjoy doing outside of work?

In the summer I do a lot of mountain biking, and in the winter, I do a lot of snowmobiling. I enjoy being in the woods away from everything.

Aluminum Extrusion Manufacturing 101: Understanding Extrusion Die Types

Whether you’re new to aluminum extrusions or a seasoned extrusion designer, it’s important to understand how an extrusion die is designed to create different profile shapes and why those differences impact the die manufacturing cost. While the upfront investment in an aluminum extrusion die may look expensive, shorter lead times and overall lower production costs make it a clear winner for many product applications.

What is an Extrusion Die?

Extrusion dies are essentially thick, circular steel disks containing one or more openings to create the desired profile. They are normally constructed from H-13 die steel and heat-treated to withstand the pressure and heat of hot aluminum as it is pushed through the die.

While it may appear that aluminum is a very soft metal, the reality is it takes a tremendous amount of pressure to push a solid log (billet) of aluminum through a thin, multi-holed die to create the desired shape. In fact, it takes 100,000-125,000 psi of force to push a billet through an 8” inch press.

Aluminum Extrusion Process

To put that force into context, a power washer to clean a car pushes out water at around 2,500 psi. Increasing that pressure to 5,000 psi can destroy the brick on a building. The pressure produced in an extrusion press is 20 times that amount.

Die Profile Categories

While there are a multitude of shapes that can be created using aluminum extrusions, the dies used fall under three categories: solid dies, semi-hollow dies, and hollow dies.

Solid Dies

Solid Profile Extrusion Die Set

Solid Profile Extrusion Die Stack

A solid die creates a final shape that has no enclosed voids/openings, such as a rod, beam or angle. As such, a solid die is typically less expensive to manufacture than other die types.

To produce a solid profile requires a set of parts called a “die stack.” This stack is made up of:

  • Feeder plate controls the metal flow through the die orifice.
  • Die plate forms the shape.
  • Backer plate supports the tongue of die to prevent collapse or distortion.
  • Bolster supports the extrusion load transmitted from the die and backer.

Hollow Dies

Hollow Profile Extrusion Die Stack

Hollow Profile Extrusion Die Stack

A hollow die produces profiles with one or more voids, such as a simple tube with one void or a complex profile with many detailed voids. To produce a hollow shape requires a different die set, which includes:

  • Mandrel is located inside the die and has two or more port holes to generate the internal features of the profile and to control the flow of metal. During extrusion the aluminum billet separates into each port and rejoins in the weld chamber prior to entering the bearing area. The ports are separated by webs, also known as legs, which support the core or mandrel section. Because of these extra components, a hollow die has a higher material and tooling cost, and typically get more expensive the more voids are included.
  • Die Cap is a multi-piece die which makes the shape.
  • Bolster supports the extrusion load transmitted from the die cap and mandrel.

Semi-Hollow Dies

Semi-Hollow Profile Extrusion Die Stack

Semi-Hollow Profile Extrusion Die Stack

A semi-hollow die extrudes a shape that is nearly hollow, partially enclosing a void. Similar to a hollow die, a semi-hollow die set includes a mandrel with port holes, but without cores to make a complete void, as well as a die cap and bolster.

While a solid die may also partially enclose a void, the difference is the ratio of the area of the void to the size of the gap where the tongue is connected to the main body of the die. This ratio is called the tongue ratio. For semi-hollow dies, the tongue ratio is larger than in a solid die, which creates more complexity when manufactured, and in turn more cost.

How Long Do Extrusion Dies Last?

Heat buildup and uneven pressure caused by a profile’s design—use of thin walls, unbalanced shapes, and protruding legs—are the biggest killers to the longevity of an extrusion die. An experienced extruder will design the die to control heat and uneven pressure and slow the extrusion rate to extend the life of a die, but eventually dies must be replaced. Fortunately for designers, most extruders absorb the cost of die replacements.

However, a designer should understand which design decisions will most dramatically impact their upfront tooling costs before sending a design to an aluminum extruder. Changes, where possible, to a profile’s design, tolerance settings, and alloy could save you thousands of dollars in tooling costs.

Learn more about die tooling in our informative whitepaper, 7 Design Decisions that Increase Your Die Tooling Costs.

4 Things to Always Include on Your CAD Profile Drawings

Aluminum Extrusion CAD Drawing

CAD software is an essential tool for today’s industrial designers to explore both form and function of their design ideas. In addition to better visualization of product designs, CAD software is being used to analyze strength and dynamic assemblies helping lower product development costs and greatly shortened the design cycle.

While we still get a few designs on napkins, most designers send us their aluminum extrusion profiles as CAD files. Unfortunately, these drawings sometimes lack important details or have issues that create a lot of back and forth between our manufacturing team and a designer to produce a production quote.

To save yourself time and cost, here are four things to always include in your CAD file when sending an aluminum extrusion profile to your manufacturer.

  1. Make Sure Your Drawings are Readable

Precise measurements are necessary to understand the component’s dimensions and shape and determine the proper container size needed for producing the extrusion die. While CAD drawings are ideal, if your dimensions aren’t readable, can’t be traced to the feature, or the drawing is too cluttered it’s going to create problems.

Do not use too many dimensions on drawings and details. Use only the dimensions that are needed to properly illustrate drawings and details. If two dimension lines show up close together, either put a note on one dimension to clarify what feature it refers to or apply dimensions in a logical flow.

Proper CAD annotation format

Use clear, standard (simple) Geometric Dimensioning and Tolerancing (GDT) call outs with standard Datum call outs. Do not reinvent the GDT handbook. And remember, the more datums you use for fabrication, the more costly the component.

If the shape is complicated, such as requiring compound miter cuts, cutout shape locations in relation to extrusion walls, etc. include the following file types .DXF and/or AutoCAD .DWG / Solid Works .STP file.  Also, indicate “exposed surfaces” on your design drawing so the extruder can give them special attention and protect the finish during both extrusion and post-extrusion handling.

Lastly, verify your drawings show the proper scaling and measurement units English/Imperial or Metric units. Double checking that you start out with the correct scaling and units will save time in the end.

  1. Be Consistent with Your Tolerances

Consistency in tolerancing methods is every bit as important as consistency in dimensioning. As a reminder, tolerance is used to control the amount of variation inherent in all manufactured parts, in particular for mating parts in an assembly. The use of plus/minus (+/-) dimensioning provides the allowable positive and negative variance from the dimension specified.

Most designer use plus/minus (+/-) dimensioning, but some may opt to express dimensional data with double minus or positive tolerances, which is also an acceptable style. Regardless of which style you prefer, it is important you maintain consistency throughout your drawing to make it easier for the extruder to interpret, saving time and reducing errors. Also, use tolerance extrusion dimensions that can be easily checked with calipers and other handheld inspection tools.

Tolerance Settings

If you have custom specific tolerance specifications, and you have a document that calls that out, be certain to supply that document. If it is not sent, your manufacturer will either have to request it from you or have to provide a quote and note that your custom tolerances were not used.

  1. Check Your Tolerance Settings

While standard industry tolerances usually provide adequate precision for most applications (these tolerances are published in the Aluminum Association’s Aluminum Standards and Data Guide), more complex components may call for greater geometric dimensioning and tolerancing in order to achieve the shape-related intricacies of the design. When requested, very precise tolerances of 1/2 or 1/3 of the specified tolerance may be feasible. For example, if the tolerance calls for + or – .010, a tighter tolerance of perhaps + or – .005 could be held, when requested and deemed feasible.

However, to achieve these tighter tolerances may require more involved die corrections, slower extrusion rates, and sometimes a higher rejection rate. All that special care adds up to higher costs. Therefore, carefully consider the application of your part or product when setting tolerances.

A good rule of thumb is NOT TOLERANCE ANYTHING that doesn’t absolutely have to have a tolerance. Aluminum Association standard tolerances will be applied wherever tolerances are not specified. But do ensure you always identify your Critical to Function (CTF) tolerances, such as areas where you are mating hardware.

Pay close attention to the default settings in your CAD programs. Using the default numbers on your drawing program when the decimal setting is three or four places out means every dimension shown appears to require the highest precision.

  1. Calculate Your Tolerance Stack Up

Tolerance Stack UpIf you are designing parts that assemble, also be aware of tolerance stack up. Tolerance stack-up calculations represent the cumulative effect of part tolerance with respect to an assembly requirement. By adding tolerances to find total part tolerance, then comparing that to the available gap or performance limits, you can determine the probability that a part will have a poor or impossible fit with a mating part.

Most CAD software programs include a tolerance analysis tool. Use these tools to automatically check the effects of tolerances on parts and assemblies to ensure the consistent fit of components and to verify tolerancing schemes before sending a profile to your manufacturer. If your program doesn’t include an analysis tool, there are a variety of analysis methods you can choose from and can calculate using a spreadsheet.

Don’t Be Afraid to Ask Your Extrusion Provider for Help

Whether you’re new to aluminum extrusions or a seasoned extrusion designer, your aluminum extrusion manufacturer can help you figure out proper tolerances and stack up, saving you time and frustration. Best-in-class extruders like Vitex work directly with designers to ensure their designs take full advantage of all aluminum extrusion manufacturing functions.

Do you have a project using aluminum extrusion? See how Vitex can save you time and money. Request a no-obligation quote or design review today.

BIA Business Perspective: To NH Lawmakers — Tread Carefully On Energy Legislation

Written by Andrew Curland, Vitex Extrusion CEO & President and incoming BIA Chairman-elect on May 11, 2019

This article originally appeared in New Hampshire Union Leader

Vitex Extrusion is one of many advanced manufacturing businesses in New Hampshire. At our 115,000-square-foot facility in Franklin, we have the capability to produce 30 million pounds of custom aluminum extrusions and components for industries including electronics, building products, automotive and sporting goods.

We manufacture 24/7, meaning we use a lot of power to run our industrial machinery, lights and HVAC equipment. One of the highest operational costs for Vitex is electricity.

This session, the New Hampshire Legislature is pursuing policies that will — alarmingly — add to the cost of electricity and require subsidies from businesses, including Vitex, and residential ratepayers like you. These policies make it difficult for manufacturers, who drive the state’s economy like no other sector, to grow our companies here in New Hampshire.

In fact, expanding in New Hampshire is a growing concern for some of us. New Hampshire individual and business electric ratepayers already absorb energy costs that are 50 to 60 percent higher than the national average — year-round! Still, many bills under serious consideration by legislators this session not only fail to lower electric costs, but instead add to them.

The legislation with the largest potential cost impact for businesses and all ratepayers seeks to increase the state’s minimum percentage obligation for New Hampshire’s Renewable Portfolio Standard, known as RPS. Many states around the nation have adopted RPSes of their own that require a portion of electric utilities’ mix of generation supplied to customers must come from renewable sources such as wind, solar, hydro and thermal.

New Hampshire currently requires that 17 percent of utilities’ energy must come from renewables; that percentage increases to 25 percent by the year 2025. Two proposals this session aim to raise the RPS percentage to 56 percent by 2040. The increase in the 21-year period between 2019 and 2040 called for in this legislation is estimated to add up to $5 billion in electricity costs for New Hampshire ratepayers — businesses, homeowners and renters alike.

With the region already hard-pressed to meet its current electricity demand (grid operator ISO New England predicts a high likelihood of rolling blackouts by the winter of 2024-25 if our regional energy situation remains unchanged), legislators should tread carefully with this legislation. Supporting clean energy and renewables as part of an “all of the above” approach is important in attempting to address high electricity costs. However, there needs to be a healthy balance between the pursuit of clean energy and the need to ensure reliable power at all times, and to do so at rates that are at least stable, if not declining.

In addition to RPS legislation, lawmakers are once again considering subsidizing biomass plants in New Hampshire by requiring utilities to purchase baseload renewable generation at above-market prices. This cost, estimated to be about $25 million annually for three years, would again be passed on to all ratepayers. This language follows a similar bill that was vetoed by Gov. Chris Sununu last year, then overridden by the Legislature.

Although this legislation would seek to protect jobs in the woods products industry, mostly in the North Country, it comes at the expense of energy users, particularly large ones like Vitex, which employ tens of thousands of people throughout the state. It is simply bad public policy for policymakers to choose winners and losers in various sectors of the state’s economy.

Finally, legislators are once again trying to raise the cap on net energy metering from one to five megawatts. Net metering allows consumers who generate excess electricity through their own solar arrays, wind generators or other means, to receive credit for energy sent back to the electric grid. Raising the cap on net metering isn’t the issue — and should, in fact, be aggressively promoted. The issue is the amount of credit those who generate excess electricity are given. The amount of credit in these bills is likely to fall above the “avoided cost,” a figure set by the state’s Public Utilities Commission. The “avoided cost” includes the wholesale cost of power and ancillary services related to generation. Anything paid to net metering customers above the avoided cost means other ratepayers are subsidizing them. That’s simply not fair.

Instead of protecting electricity customers to the greatest extent possible from the high cost of electricity, many policymakers seek to advance policies that will further burden electric ratepayers. If New Hampshire seeks to retain existing businesses like Vitex and enable us to expand, then policymakers should be working to lower electricity costs, not increase them.

Employee Spotlight: Joe Reardon, Jr., Production Schedule Coordinator

Joe Reardon Extrusion Production CoordinatorJoe Reardon learned the aluminum extrusion business from the ground up. Having held a variety of positions during his seven years with Vitex, he has a deep understanding of how all the various processes integrate to make a finished product. This knowledge has brought him to the key position of Production Schedule Coordinator and makes him an invaluable part of our production team.

Q & A with Joe Reardon, Jr.

How long have you worked at Vitex and what positions have you held?

I’ve been here for about seven years. My dad, a long time employee at Vitex, encouraged me to apply after I graduated from high school. I started as a recut saw operator, then moved to extrusion saw operator, then stretcher operator, then press helper. I was then promoted to press operator, to extrusion press supervisor, and then to my current position as Production Schedule Coordinator. I learned a lot about the business process as I moved through these positions.

What have you learned while working at Vitex?

I learned the importance of persistence and mentorship. This was my first job. After I started, my supervisor was concerned I was in over my head because I was new and there was so much to learn. I was transferred to the fabrication side of the business for a while, but I knew I wanted to get back to the extrusion side. I worked hard, focused on my goal, and proved myself so I could move back to the extrusion line. My supervisor, Chris Bartz, saw that I am a fast learner and moved me up as I gained skills. Initially, this was just a job, but over time and with the help of mentors here at Vitex, it has become my career.

Tell us about a favorite project you’ve worked on?

I worked with my dad to build the racks for our stacker system. At the extrusion saw, the aluminum used to be stacked by hand by two workers. When the system was automated, we needed a steel rack built to specifications so the aluminum can be stacked automatically. I had never done steel work before. This project was a great opportunity to learn from my dad how to weld, grind, and cut steel. I’m very proud of this project.

What do you enjoy doing outside of work?

I enjoy bass fishing and watching professional football – particularly watching the Patriots win!

Tell us something you enjoy about working at Vitex.

The people here are great and make Vitex a truly great place to work. There is a real sense of camaraderie and everyone understands it takes teamwork to make things happen.

What advice would you give to new hires at Vitex?

The best advice I can give is to own your mistakes and take pride in your achievements.

Six Tips for Aluminum Extrusion Dimensioning and Tolerance

Aluminum Extrusion Dimensioning

Many products must be manufactured to precise standards. Questions like: How straight is straight enough? How flat is flat enough? How uniform must a wall thickness be to be acceptable? are not abstract. The specified, acceptable range of deviation from a given dimension is known as a tolerance. For many applications, in which an aluminum extrusion will be part of an assembly of components, dimensional tolerances are critical. Designers should be aware of the standard dimensional tolerances to which extrusions are commercially produced. Tight tolerances can decrease productivity, which leads to higher production costs. Judicious use of high tolerances only where they are essential to the productivity of the profile will help keep costs and deadlines in check.

Here are six tips to help you use the most appropriate dimensioning and tolerance for your aluminum extrusion parts.

  1. Choose Only Critical Dimensions

Trying to achieve tolerances on non-critical dimensions is a major source of hidden costs. Frequently, designers put too much emphasis on tolerances that do not affect the form, fit or function of the final product. These non-critical dimensions can result in longer setups or repeat runs, which can lead to costly, late or rush deliveries. Designers can decrease those costs by identifying only the most critical product dimensions.

  1. Understand Which Tolerances are Achievable

When the designer has defined the most critical product dimensions, the next step is to understand which tolerances are achievable based on the specific manufacturing process. Tolerances are affected by multiple factors, including press size, billet temperature, extrusion speed, die shape and type, cooling time, and air temperature. To help designers, the Aluminum Association has developed industry standard tolerances for extruded products. Designers can use these as a reference guide when designing a product. If tighter tolerances than the standards are needed discuss the required tolerances with your aluminum extrusion expert.

  1. Collaborate Early With Your Aluminum Extruder

To understand tolerance expectations, it’s important to involve the aluminum extrusion experts in the initial stages of design. It is important that the designers rely on the extrusion professionals to understand tolerance standards as well as how various factors, including aluminum temperature, cooling time and the speed of extrusion – impact each part of the design.

  1. Establish Critical Product Measurement (CpK) Values

Establishing the CpK value to be used is a critical element in determining capability of dimensional tolerances. Some CpK requirements will necessitate a capability study to determine the extent to which the extrusion process can meet specified dimensions. Although this is an added cost it will allow the extruder to understand process capability and repeatability. Process capability indices measure the degree to which your process produces output that meets the customer’s specification. Determining the accuracy and precision of your process will allow you to estimate the number of failures that can be anticipated.

  1. Understand Geometric Tolerancing

When tolerances are met, parts fit together well. They perform as intended, and do not require unnecessary machining. Geometric dimensioning and tolerancing can be used to specify the shape of an extrusion on an engineering drawing. It is likened to a technical language, which has uniform meaning to all; this can vastly improve communication in the cycle from design to manufacture. It more readily captures the design intent by providing designers and drafters better tools with which to communicate their needs. It adds a new dimension to drawing skills in defining the part and its features. When an engineer is concerned about fit and function geometric tolerancing is structured to better control parts in a fit-and-function relationship.

  1. Design for Both Functionality and Manufacturability

Dimensioning a part for functionality without considering manufacturability often creates added cost and frustration. Keeping the dimensioning format simple as will help keep costs down by reducing excess machining operations, re-clamping and handling operations, while also reducing process variation.

These tips offer an alternative to defaulting to block tolerances. By partnering with your aluminum extrusion manufacturer early in the design process you can plan and design for both functional and manufacturing goals.­

Have a design project? See how Vitex can save you time and money. Request a free design review today.

Improve Product Design by Understanding Accuracy, Precision and Tolerance

Precision Tolerances for Aluminum Extrusions

CAD software is just about every designer’s go to tool for product design. These programs enable simpler and more accurate design iterations, and comprehensive documentation for the manufacturer to make the actual part. They are also capable of drawing dimensions that are far more accurate and exacting than can be actually manufactured. This results in final designs being sent to the manufacturer only to get kicked back with a note that the design is “not manufacturable” or the cost to manufacture is far more than was budgeted due to the requirements.

Understanding the difference between terms like “accuracy,” “precision” and “tolerance” is important if you want to manufacturer your product designs more quickly, easily and with better results.

Understanding Accuracy, Precision and Tolerance

Accuracy, precision and tolerance may seem similar and sometimes they are used interchangeably. However, when designing an aluminum extrusion understanding the differences and nuances of these terms can be key to a more efficient and cost-effective design. Sometimes more accuracy, greater precision and higher tolerance are beneficial to your design; sometimes they offer little benefit and some drawbacks. Learning these subtleties will help you make smart design decisions.

What is Accuracy?

The first term, accuracy, can be defined as the degree to which a measurement conforms to a standard. Modern CNC cutting tools are typically very accurate. So, for example, if a machine is programmed to cut the extrusion to 60mm long, it cuts it to 60mm; accuracy is how close to exactly 60mm it gets with no error. The closer to the standard the greater the accuracy. However, more accurate is not necessarily better for many applications. Greater degrees of accuracy may seem like something to strive for, but it can be counter-productive. Achieving ever greater degrees of accuracy costs time and money usually with diminishing returns. Also, getting high accuracy in one area of a design often requires sacrificing accuracy elsewhere.

What is Precision?

Precision ensures the end product turns out the same every time. That is, the creation of perfect, precise products time after time. You may often see or hear the terms “precision manufacturing,” “precision engineering,” and “precision machining.” All refer to the use of automated machinery to deliver precision. The way that precision can be measured is by specifying tolerance.

What is Tolerance?

Tolerance is the deviation away from a known value. For example, if a machine tool has a tolerance of “+/- 1mm” this means the tool can potentially introduce a deviation of 1mm (or some fraction of a mm) longer or shorter than the specifications. When designing parts to be extruded, your measurements need to account for the expansion and contraction of your materials. You don’t want parts to fit together too tightly, without clearance. This would mean they are immovable, or impossible to assemble. Good design means allowing for this natural movement.

Making tolerances tighter may seem like a good idea, but sometimes tighter tolerances may not be necessary and will not benefit the finished product. Tighter tolerances will drive up cost and take the manufacturer longer to produce. Reviewing tolerances with your aluminum extruder early in the design process can help you identify if there are any issues with tolerance settings.

Work with Your Aluminum Extrusion Manufacturer

When designing an aluminum extrusion, it is important to understand accuracy, precision and tolerance and how they can impact your design and the manufacturing process. If you have questions regarding your next design project, Vitex can help. Our aluminum extrusion experts can complete a free design review and point out if they see any issues with accuracy, precision or tolerance settings. Request a free design review today.

Designing for Simplicity with Aluminum Extrusions

For product designers, KISS— “keep it simple, stupid”—is a well-known rule of thumb. As a design principal, it’s about making products simple and easy to understand to appeal to users. When it comes to designing for manufacturability, the simplicity principal still applies, particularly when designing aluminum extrusion profiles.

Complicated product designs and configurations produce complex development requirements. In turn, complex requirements often mean more steps and hands are involved in manufacturing a product. This often increases its overall cost and the chance for quality issues. Here are five ways designing with aluminum extrusions can simplify your product design:

  1. Eliminate or Reduce Machining

Elegantly simple designs—those with the fewest parts, interfaces, and process steps— result in fundamentally high-quality products that cost less to make. For example, an aluminum extrusion part originally designed to require machining could, with a minor design modification, be produced using a punch die to get the same end result. The part now uses a less expensive fabrication method resulting in lower cost and faster production time.

  1. Reduce Part Count

Designers can also create complex shapes with extruded aluminum to reduce part count and combine functions saving on production and overall product life cycle costs. For example, a single extruded profile can replace rolled shapes riveted together, resulting in higher strength while eliminating joining costs.

  1. Eliminate Secondary Operations

Aluminum profiles produced in near net shape can incorporate holes, slots, or screw bosses into the shape, eliminating much of secondary operations (see image below). Although the individual cost of the extrusion could be higher than a simple formed sheet steel part, the overall system parts are often significantly lower. A designed extrusion can also eliminate welded assemblies, reducing cost while increasing strength and accuracy.

  1. Tailor Metal Placement

Using aluminum extrusions is also an economical way for designers to create parts with individually engineered shapes. This versatility allows designers to place metal only where it is structurally needed and hollow out parts for greater functionality and economy. Keeping the extrusion simple in this way allows extrusion to be tailored to concentrate or add strength precisely where it is needed.

  1. Use Less Expensive Alloy

Additionally, with new advances in aluminum alloys and extrusion cooling technology, designers can use standard grades of aluminum for many applications, rather than go to a higher cost alloy. At Vitex, we can tweak the way we cool or age an extrusion to make it just as strong as a more expensive alloy. This offers manufacturers a lot of flexibility and cost savings.

Tap Your Extrusion Manufacturer for Design Guidance

Looking for ways to simplify a part or component? Your greatest resource is your extrusion manufacturer. Best-in-class manufacturers, like Vitex, will work closely with you to review the profile and tolerances to ensure your product is designed to take full advantage of all aluminum extrusion manufacturing functions. Our manufacturing team will also identify any issues and alert you if additional machining or fabrication will be needed to meet your desired requirements, and in some cases, identify opportunities to avoid additional machining.

If you are not familiar with the various alloys available, your aluminum extrusion manufacturer can offer guidance as to how the different alloys offer different capabilities that may be useful to your design. Additionally, your aluminum extrusion expert can educate you on material and tooling costs.

To learn more about how Vitex can assist you in simplifying your aluminum profile design and manufacturing process, contact us directly or request a free design review.

Keeping Costs in Check: Designing Aluminum Extrusions with Proper Tolerances

aluminum extrusion tolerances

Designers must keep an eye on the bottom line in every project. Finding creative and practical solutions to accomplish cost control while also maintaining the integrity of the design is important, but it can consume engineering resources. One often overlooked way to keep costs down is to examine tolerance requirements. With unnecessarily tight tolerances parts become more expensive to produce. In fact, customers sometimes ask us why a part is so expensive, not realizing that extending tolerances out just one more decimal point can increase the cost by a factor of two or three. That is because tighter tolerances require greater care in fabricating and inspecting in order to ensure accuracy.

Some simple steps in the planning process can help prevent over-tolerancing without compromising design or function.

Have Your Aluminum Extruder Review the Design

First perform a comprehensive tolerance review at the concept stage of the design process. Although tolerance is typically one of the topics addressed, reducing tolerances is an area of concern for most design engineers. A simple and effective solution for this concern is to improve communication between design teams working on different aspects of the project.

You should also include your aluminum extruder in the conversation to get expert advice from the manufacturing side of the project. Most best-in-class aluminum extruders, such as Vitex Extrusion, provide Design for Manufacturing support.

By working with designers early in the design process, we ensure a product is designed to take full advantage of all aluminum extrusion manufacturing functions. We review a design’s profile and tolerances and determine process capabilities to meet dimensional limits. Our manufacturing team also identifies any issues and alerts the designer if additional machining or fabrication will be needed to meet the desired requirements, and in some cases, identify opportunities to avoid additional machining.

Be Realistic About What Tolerances Are Needed

Next, determine the actual required tolerances; this is most effectively done by understanding a part’s application and interaction with other parts. Assess tolerances overall – not just of a single component – and determine if there will be any inconsistencies with outside components.

Sometimes, if there is a rush to get a design to the manufacturer, a designer may over tolerance a part just to be sure. Or, a designer may accept the software’s default tolerances without understanding whether or not they’re truly necessary, or simply not noticing them at all. Both of these actions can unnecessarily drive up cost.

Here are just a few typical examples:

  • An extra decimal of tolerance is specified not for a technical reason — that is, not because the particular part needs that level of precision — but because that is “the way it has always been done.”
  • In a project with several components requiring a tolerance of ±0.001 because of the way they must fit together, a separate part is automatically specified using the same tolerances, even though the part does not interact with the others and may or may not need the same tight tolerance.
  • In an effort to keep mechanical drawing labels consistent to the same decimal point, a zero is accidentally misplaced, labeling a tolerance ±0.001 instead of ±0.010.
  • Two parts that failed to fit together correctly are re-specified at tighter tolerances — but the original failure was due to the parts being cut at two different loose tolerances.

Understand the Cost Tolerance Equation

Ensuring designers are aware of exactly how tolerancing affects cost is another key to successfully keeping costs down. Tighter tolerances lead to higher costs. Over-toleranced parts are more costly, harder to manufacture, take longer to produce, and may be entirely unnecessary. Choose a sample project and calculate how much each tenth of tolerance costs in dollars, then multiply it by features. This knowledge will help the team be more conscious of the total cost.

Have a new design project? Vitex aluminum extrusion experts can help you determine the proper tolerances for your design and help you keep an eye on the bottom line. For more information on how Vitex can help your design team contact us.