Shear: 

  The shear is used to cut larger sheets to the desired blank size. This is usually a two step process. Larger sheet stock is fed directly into the machine until contact is made with the adjustable back gauge, then the shear is activated the blade comes down and cuts the material, step 1. The strips of material are collected and then held against the squaring arm and fed into the shear until contact is made with the back gauge, again the shear is activated the blade comes down and makes the cut, step 2. 

 This is accurate enough in most cases, however, where extreme accuracy is required the blank is cut oversize then trimmed to size by a third step known as front gaging. This results in very accurate blank sizes. Angle shearing is also possible but not recommended for precise parts. Shearing is usually the first step in the actual fabrication process. Machine: Pexto PH452, 48" x 16 ga. mild steel capacity.

Pierce:

  Hole pierce is a metal removal process that involves the use of tooling and specialized presses. Tooling consists of a matched pair, called a punch and die. Round, square, oval and rectangle are all considered standard shapes and should be chosen if possible when designing parts as special shapes can be very costly. 

  Small size tooling can be used to make larger cutouts. Different shapes can be used in combination to achieve shaped cutouts as well. The steps involved for accurate hole location are, choose the pierce tool, set the material stops, pierce the hole, measure the hole location on the blank and adjust material stops for desired hole location. 

  Three specialized Whitney manual machines are employed for hole pierce operations. These are very flexible and are best suited for smaller quantity. Don't let the words "manual machines" put you off. Accurate, flexible, and productive is a much better description of the Whitney presses. CNC plasma cut shapes can have holes pierced in them when sharp corners or close proximity features are required. Again flexibility is the key here. There is a very nice compliment of tooling available for the Whitney presses. Please email for list of available tooling. Machine: Whitney #118 4 tons pressure, Whitney #218 4 tons pressure, Whitney #29 5 tons pressure.  

Notch:

 The notcher is a form of a shear. The blade of the notcher is configured at 90°. The main use for this tool is to perform material removal operations on the perimeter of the blank. Material stops are set to limit material entry into the blade cut area. Virtually any angle can be set but usually square corners are cut or 45° chamfer operations are preformed. The notcher is a very simple tool but its versatility make it invaluable for sheet metal work. Machine: Dayton manual 4 ton notcher.

Roll:

 The slip roll is used to make round or cylindrical parts. This is not the most precise process used in sheet metal fabrication. There are some strange quirks that arise. One being the ends of parts forming a tighter radius than the center of the part, especially noticeable on wider parts. The entry end and exit end of the blank differ somewhat in their shape and radius.

Although most of these shortcomings can be overcome by part shimming during rolling and bumping a radius prior to rolling. Still you should be aware of the process and the ultimate request for tolerance adherence of the perfect radius is sometimes unattainable. Machine: Niagara 28 inch manual slip roll.

Form:

  Forming sheet metal is the process of forcing the blank to the desired angle. Tooling is selected based on the desired material stretch. The tooling consist of a punch and die but it is vastly different than pierce tooling. The basic forming explanation is, the punch, the tool which is setup in the top most position, usually above the material, forces the material into the die, the lower tool in the forming setup until the desired angle is achieved. 

  The punch radius can be used to determine the inside radius of the bend. The punch is the tool the sheet metal conforms to the most however its main involvement in the process is to limit the minimum inside radius of the bend. The bottom tool controls the material stretch the most. The bottom tool must also be selected based on the sheet metal thickness. The bottom tool must be wide enough to allow for proper clearance of material, the top tooling radius and when air forming, material spring back allowances. 

  A press brake is employed to form sheet metal into small bent shapes. Most forming is done by the air form method. Small sheet metal banks are captivated or nested under the form tooling to control precisely how the blank is contacted by the top punch tooling. By captivating the small blank, repeat angles and dimensions are insured. The press brake uses a custom designed gaging system that allows for quick, safe, accurate setups. The blank is fully supported before the forming process begins. There is a very nice compliment of brake tooling available for most forming needs, there is however to much form tooling to list. Machine: Chicago #135 15 tons pressure, custom front and back gaging system for blank nesting and blank captivation prior to forming. 

Shape Cutting:

  Complicated and unusual shapes are cut with a CNC controlled plasma machine. Plasma cutting is a process where air is forced through small holes to form a rotating vortex of air inside the cutting torch. This vortex is then electrified to ionize the air and superheat it to 15,000 + degrees F°. This heating causes the ionized air now called plasma to rapidly exit the vortex chamber through a very small hole in the cutting torch. This escaping plasma forms a tiny, hot, tornado which when located the proper distance above the metal, will remove a narrow pathway of metal in any direction the torch moves. Note, this is a non-contact process, meaning the cutting torch floats just above the material during cutting never touching the metal. 

 A PlasmaCam DHC2 is employed for the shape cutting. It is servo driven on the XY axis, stepper driven on the Z axis and is the newest precision machine tool in the shop. Being a servo driven machine it is fast and accurate. A state of the art digital height control precisely adjusts the cutting height of the plasma torch keeping it at the desired cutting distance above the material surface. The PlasmaCam software is very effective in cutting path conversions and also part designs. Shapes that once required many steps to manufacture are now done in one setup on the DHC2. Fine cut consumables are used throughout for a less heat effected cut zone and for finer detail cutting. This machine is setup to cut thiner gauge sheet metal. Machine: PlasmaCam DHC2 , Hypertherm PowerMax 380 plasma cutter, FineCut® consumables. 

Tumble:

 Tumbling is a process of abrasive contact machining. Often small sheet metal shapes have sharp edges after being sheared and having holes pierced. Tumbling these shapes is a very efficient way of removing the sharp edges. Media, the abrasive ceramic shape, and the small bent shapes are place into a vibrating bowl together. The vibrating abrasive action wares away the sharp edges leaving a part virtually burr free and safely handled with out any worry of being injured. This action will not change the part dimensions although it will leave a dull finish on the small bent shape. Machine: BurrKing 200sx Vibratory with adjustable frequency, capacity 20 quarts, 35 lbs. media with 15 lbs. bent shapes.

Machining:

  Machining is a process of material removal in-which either the part rotates and a stationary cutting tool removes material or the cutting tool rotates against stationary material for material removal.

  A manual mill with a DRO is employed for shop support, tooling modifications and for welding fixtures. Manual toolroom lathe is employed for shop support and tooling modifications. Manual surface grinder is employed for pierce tool sharpening and shop support. Machine: Bridgeport J-head mill 9x42 table and power-feed with DRO, Harrison 10AA toolroom lathe with quick change tooling, DoAll 6x12 manual surface grinder, RongFu band saw, Craftsman 17 inch drill press. The quantity of stocked tooling on hand is not enough to support acceptance of machining type orders.  

Weld:

  TIG welding is an electrical process where the base metal is control melted in a non oxygen atmosphere by a tungsten electrode connected to a welding power source. The melted sheet metal bent shape edges can be fused together or a filler metal can be added to the molten metal pool before it solidifies thus joining the bent shapes together to form a precision weldment.

  A 250 amp TIG welder is employed with a liquid cooled torch and a pulse control unit. Also in use is a electronically controlled auto darkening welding helmet. Aluminum, Steel and Stainless can all be successfully welded by the TIG process. Machine: Miller Syncrowave 250 TIG welder with a Miller Pulse controller, Jackson EQC Professional weld helmet.

Finishing:

Sheet metal shapes are usually made ready for painting, plating and safe handling prior to shipping.

Surface prep, edge deburr, smooth of welds by grinding, hand deburr, straight line finish services can be preformed.

Summation:

 The capability list of this shop might seem quite small, but again this is a very focused specialty shop. When you combine all the services together, this shop has much more flexibility and is much more capable than it may first appear.

The Untold Story:

 The inspiration for starting this shop was the most simplest of parts. This small part had one small hole and one bend, it was considered a nuisance part for the shop I was working in. It was however the inspirational foundation of Martin Sheet Metal. I remember holding that small part and thinking, "maybe one day I could start a shop and make small parts". That simple small part with one small hole and one bend changed my life forever.

 Never overlook the simplest things in life, they may be hiding something truly inspirational.

Acknowledgment:

 Thank You for visiting Martin Sheet Metal World. If you have any unanswered questions, pierce tooling list, or full equipment list, please visit the contact page I will be happy to send the lists to you by email.