November 1, 2020

Sourcing the Best Sheet Metal Prototypes in 2020

If you’ve worked with different fabrication and prototyping services, you know that they aren’t all created equally. PROTOTEK is known for our quick turnaround on sheet metal and machining parts, starting with our rapid quoting. That’s why so many engineers and designers rely on PROTOTEK as their “one-stop-shop” for all of their part needs.

PROTOTEK: A One-Stop Sheet Metal Fabrication Company


  • Fast-Flexible Personalized Service
  • Quotes in 24 Hours
  • Same Day or Emergency Jobs – Call 1-800-403-9777
  • Precision Sheet Metal Parts & Assemblies in as Fast as 1-3 Days
  • CNC Milled and Turned Parts in as Fast as 1-3 Days
  • Finishing Options in House – No Added Delivery Time
  • We Bid Complex Jobs – Don’t Get No Bid
  • Silk Screening and Laser Engraving
  • ISO-9001 Certified, ITAR Registered
  • Estimates With or Without CAD Models

What is Precision Sheet Metal Fabrication?

When people talk about sheet metal fabrication, they are discussing the process that is used to manipulate materials to create a component that will be used in an end product. It involves a material being cut, formed and finished. Sheet metal fabrication is used in pretty much every sort of manufacturing field, notably in medical equipment, computers, electronics and appliances. Essentially, anything that is constructed out of or contains metal will have gone through these processes:

  • Cutting
    There are a number of ways that sheet metal can be cut into smaller pieces – shearing involves a cutting machine using shear stress to cut down a large piece of material into smaller ones; electrical discharge machining (EDM) involves conductive materials being melted with a spark from a charged electrode; abrasive cutting involves the use of grinders or saws to cut through material; and laser cutting involves the use of a laser for achieving precise cuts in sheet metal.
  • Forming
    After the metal has been cut, it will be formed into what shape is desired for the component it is needed for. There are several techniques of forming that can be used – rolling involves flat pieces of metal being shaped over and over with a roll stand; bending and forming involves the material being manipulated by hand; stamping involves the use of tools to stamp designs into the sheet metal; punching involves holes being put into the surface; and welding involves one piece of material being joined to another using heat.
  • Finishing
    Once the metal has been formed, it will be passed through a finishing process to ensure it is ready for use. This will involve the metal being sharpened or polished with an abrasive to remove or eliminate rough spots and edges. This process may also involve the metal being quickly cleaned or rinsed to ensure that it is completely clean when it is delivered to the factory for its intended purpose.

As you can see, sheet metal fabrication is highly important in the creation of any component that contains metal (from your laptop all the way through to the paperclips holding your files together). If you do not have the time or the resources to fabricate your own materials, you can employ a specialist fabricator to do this for you. Not only will this give you more time to focus on creating your products, it will ensure that you receive the best finish possible on your metal components.

  • Metal fabrication is the creation of metal structures by cutting, bending and assembling processes. It is a value-added[1] process involving the creation of machines, parts, and structures from various raw materials.
  • Typically, a fabrication shop bids on a job, usually based on engineering drawings, and if awarded the contract, builds the product. Large fab shops employ a multitude of value-added processes, including welding, cutting, forming and machining.
  • Metal fabrication usually starts with drawings with precise dimensions and specifications. Fabrication shops are employed by contractors, OEMs and VARs. Typical projects include loose parts, structural frames for buildings and heavy equipment, and stairs and hand railings.
  • As with other manufacturing processes, both human labor and automation are commonly used. A fabricated product may be called a fabrication, and shops specializing in this type of work are called fab shops. The end products of other common types of metalworking, such as machining, metal stamping, forging, and casting, may be similar in shape and function, but those processes are not classified as fabrication.

Sheet Metal Materials

When people talk about sheet metal fabrication, they are discussing the process that is used to manipulate materials to create a component that will be used in an end product. It involves a material being cut, formed and finished. Sheet metal fabrication is used in pretty much every sort of manufacturing field, notably in medical equipment, computers, electronics and appliances.

  • Materials we work with include ESD-safe plastics and metals including Titanium, Gold, Copper and
    Stainless Steel.
  • We also work with ABS, Corzan, Delrin®, Ertalyte®, Kevlar, Kynar®, Lexan®, Nylon, PE, PP, PU,
    PlexiGlas®, PVC, Radel®, Ryton®, Semitron, Torlon®, Ultem®, Vespel® and Victrex®.

Sheet Metal Design Considerations

  • The following sections address common areas.
  • We specialize in the impossible, but by aligning to better designs, you can often save money on the cost of a part.

Corner Construction

Corner Construction Types and Tips

prototek overlaps

Full Overlap: Typically chosen when welding is not needed. Ensure proper bend relief is being used at the intersection of the 2 bends. This corner construction is the most economical choice and should be chosen where there is no need to secure the corner of a sheet metal part.

Half Lap: A preferred choice for steel and stainless parts when welding is required. This will allow for proper weld penetration and limit the amount of heat required when welding, which in turn will help reduce distortion. Proper bend relief should be ensured for half lap construction.

Open Corner: Chosen for Aluminum parts where as full weld penetration is important. Typically there is no need for bend relief when open corner construction is chosen. Open corner construction can also be used for other materials where parts are subject to high stress environments.

Spot Weld Flanges: Another popular choice for corner construction. This construction is not seamless like fully welded corners but can be a more economical. Proper bend relief and alignment holes should be considered when choosing to add spot weld flanges. Alignment holes can be filled with weld and ground smooth if required.

Pop Rivet Flanges: Similar to spot weld flanges are typically the most economical choice to secure the corners of a sheet metal part. Holes are added thru the walls with flanges where pop rivets are inserted to secure the corner.


What are bends?
Adding bends to a flat sheet of metal transforms that metal into a three-dimensional piece. Prototek uses a press brake tool for air bending, coining and bottoming. We can also work with designs needing three-point ending, folding, wiping, rotary bending, roll bending, elastomer bending and joggle bending.

Design considerations

Wall Thickness

What is wall thickness?
Wall thickness refers to the overall thickness of the metal being used to create the part. Sheet metal parts are created from a single sheet of metal. This means, the part needs to maintain a uniform wall thickness. Prototek can manufacture sheet metal parts ranging in thickness from .0.010 inches to .25 inches.

Design considerations

wall thickness best practice

Bend Relief

What is bend relief?
Bend reliefs help strengthen transitions from bend to flat surface (or from bend to another bend) in sheet metal. When a bend is made close to an edge, there is the risk the material may tear. Bend reliefs are small cuts in the material perpendicular to the bend to help prevent tearing.

Design considerations

bend relief

Slots and Holes

What are some design guidelines around slots and holes?
Holes and slots generally need to follow guidelines around sizing and be placed at certain distances from edges and bends to avoid material warping and to maintain structural integrity. If hardware inserts are required, spacing should be according to manufacturer’s specifications.

Design considerations

slots best practices

Tabs and Notches

What is notching?
Notching is a metal-cutting process used on sheet-metal or thin bar-stock, sometimes on angle sections or tube. A shearing or punching process is used in a press, so as to cut vertically down and perpendicular to the surface, working from the edge of a workpiece. Sometimes the goal is merely the notch itself, but usually this is a precursor to some other process: such as bending a corner in sheet or joining two tubes at a tee joint, notching one to fit closely to the other.

What is the difference between a notch and a tab?
Notching is a metal-cutting process in which an intrusion or cut is made on edge of the sheet metal while a tab feature is created by adding material to the walls of sheet metal component.

Design considerations

notches best practice


What is hemming?
Hemming in sheet metal fabrication is when the edge of the sheet is folded back on itself, or folded over another part in order to fasten two sheet metal parts, to improve the appearance of a part, reinforce part edges or to increase the part stiffness. Hems can be open or closed.

Design considerations



What are countersinks?
Countersinking is commonly used for holes that need to accept a flat head screw or fastener, when the hardware needs to be flush with the surface of the part. They can be created either using machines like a drill press or formed with punch press tooling.

Design considerations



What is PROTOTEK’s welding method?
Welding in sheet metal is used to seal the edges of bent parts. Prototek offers resistance spot welding (RSW), gas metal arc welding (MIG) and gas tungsten arc welding (TIG). The type of welding will vary for each individual project.

Design considerations



What is an offset in sheet metal?
Offsets are a double bend on a piece of sheet metal that adds a second tier to your part, typically shaped like a z.

Design considerations


Hardware Resources

Common Rejected or No Bid Prototypes

Received a no bid on your prototype?
Many companies will no bid complex forming operation or non-standard materials because of the expertise and machining needed to be able to deliver on it cost effectively.

One of the things that makes Prototek different is its ability to handle the “impossible” jobs – having the capability to quote most any prototyping project across processes and finishes.

What are Commonly Rejected Sheet Metal Forming and Materials?
Below is an image and list of some sheet metal examples commonly rejected.


  • Embossing
  • Dimples
  • Card Guides
  • Knockouts
  • Bridge Lancing
  • Ground Stamping
  • Progressive Ribs
  • Progressive Louvers
  • Custom Hinges
  • Exotic Forming – can work outside machine parameters
  • Forming of Polycarbonates
  • Extruded Taps
  • Corner Gussets

At Prototek, we handle everything above and more.


Prototek utilizes a multi-step process of anodizing & finishing which includes cleaning, treatment, anodizing, coloring, sealing, and numerous quality rinses in between each phase. We focus on controlling the pH, temperature, concentration, frequency, and duration. Our technicians maintain multiple controls in the tank to ensure a consistent, quality coating. As industrial craftsmen, these processes and quality phases are the art and science we take pride in to deliver high-quality parts to our partners.

Prototek offers:

  • Powder-coating
  • Painting
  • Silk-screening
  • Laser engraving
  • Chem-film
  • Anodizing
  • Bead blasting
  • Tumbling


ventilator rapid covid19 deployment

Rapid Deployment for COVID-19
Prototek helped Meter build the Rise Emergency Ventilator for rapid COVID-19 Deployment. Our Sheet Metal Fabrication facility was chosen to expedite parts on a critical timeline. Meter LLC an industrial hardware startup based in Boston and San Francisco, developed a new concept for meeting the global ventilator shortage.

Prototek FAB 40 2020 award

Prototek Name to The Fabricator‘s 2020 FAB40
Prototek is honored to be named to this distinguished FAB 40 list of the nation’s Top 40 Sheet Metal Fabricators by The Fabricator magazine.