A material, starting in the form of a billet or slug, is pushed and/or drawn through a die of the desired profile shape. Hollow sections are obtainable by the placing of a pin or piercing mandrel inside the die.
Classification of “Extrusions” are broken down as follows:
- Impact Extrusions:
(usually < that a 2 ½” inch profile)
Aluminum, Copper and some Brasses
Standard tolerances +/- 0.003; Key tolerances of +/- 0.001”
(usually from 2 ½” up to 20”, yet the majority of extruders work up to an 11″ profile)
Aluminum, Copper and some Brasses.
Aluminum: +/- 0.008” per inch up to 1”, +/-0.08” for each additional inch.
Copper & Brass: +/- 0.020” per inch up to 1”, +/-0.020” for each additional inch.
A “slug” is placed into a die cavity, then struck by a punch forcing the metal to flow outward back over the punch, or forward, or a combination.
Aluminum, Copper, and some Brasses
Aluminum – +/- 0.005” per inch up to 2”, +/- 0.003” for each additional inch
Metal alloy stock, in sheet or roll form, is shaped (bent, pierced, and/or punched) by means of forming dies and punches, resulting in a pre-determined finished shape.
Classifications of “Stampings” are broken down as follows:
- Short Run Stampings (typically 1 to 30,000 pieces):
- Progressive Die Stampings: (typically over 30,000 pieces):
- Deep Drawing (also called Deep Drawn):
Metal sheet stock is placed into individual turret presses, realizing one tool is required for each operation (i.e.: blank, form, pierce)
+/- 0.005” on lineal dimensions; +/- 0.0015” on hole diameters.
Metal Stock in roll form is “shaped’ as it passes through multiple stages in the press. With each stroke of the press, the progressive die forms each operation simultaneously as the part moves through the press, resulting in a finished part.
All Metals that come in roll form
+/- 0.002” on lineal dimensions; +/- 0.001” on hole diameters.
Deep draw is the process of forming sheet metal into seamless one piece housings. In general, deep drawn cases come in round, square or rectangular shapes. The term deep drawn refers to the fact that the depth of the shape is greater than the width. Metal enclosures can also be shallow drawn. Additionally, dimensional tolerances can be held more closely than other forms of metal processing.
Cold rolled steel, stainless steel 200-400 series, aluminum, copper, brass, Monel®, titanium, Hastalloy®, Kovar®, nickel, Inconel®, Mumetal®, Cupro nickel, nickel silver and others.
1/16″ to 18″ (1.6 mm to 457 mm) diameter; Lengths up to 18″ (457 mm); Material thicknesses .002″ to .250″ (0.05 mm to 6.35 mm).
Round, Square, Rectangular and Asymmetrical. Flat & Corrugated metal diaphragms: 0.200″ to 18.00″ diameter / 0.0010″ to 0.0180″ thickness.
as low as +/- .002″ (.05 mm) on custom cases; as low as +/- .0005″ (.0127 mm) on precision headers; Drawn corner radii as small as .005″ (0.127 mm)
Sheet Metal Fabrication:
Usually thought of for larger parts that require individual attention (bending, cutting, forming & joining), sheet metal fabrication still is a major manufacturing process. All materials can be formed, with thickness of metal varying from 0.020” (0.5mm) up to 0.25” (6.5 mm). Thinner sheets are called “foil”, and thicker called “plate”. It is always critical to discuss beforehand Hole Size, Distance from Bends, Flange Size and Bend Radii. As equipment improves each year, the precision aspect continues to tighten, but a general rule of thumb is +/-0.05” (realizing that too tight maybe too costly).