Fabrications

Extrusions:

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:

1. Miniature:
(usually < that a 2 ½” inch profile)

Metals:
Aluminum, Copper and some Brasses

Tolerances:
Standard tolerances +/- 0.003; Key tolerances of +/- 0.001”

Surface Finish:
32 RMS

2. Conventional:
(usually from 2 ½” up to 20”, yet the majority of extruders work up to an 11" profile)

Metals:
Aluminum, Copper and some Brasses.

Tolerances:
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.

Surface Finish:
32 RMS

3. Impact Extrusions:
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.

Metals:
Aluminum, Copper, and some Brasses

Tolerances:
Aluminum - +/- 0.005” per inch up to 2”, +/- 0.003” for each additional inch

Surface Finish:
32 RMS

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Metal Stampings:

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:

1. Short Run Stampings (typically 1 to 30,000 pieces):

Metal sheet stock is placed into individual turret presses, realizing one tool is required for each operation (i.e.: blank, form, pierce)

Metals:
All Metals

Tolerances:
+/- 0.005” on lineal dimensions; +/- 0.0015” on hole diameters.

2. Progressive Die Stampings: (typically over 30,000 pieces):
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.

Metals:
All Metals that come in roll form

Tolerances:
+/- 0.002” on lineal dimensions; +/- 0.001” on hole diameters.

3. Deep Drawing (also called Deep Drawn):
Metal stock in roll form is subject to deformation by using a die and punch. As with progressive die stampings, with each stroke of the press, the metal is deformed more and more creating a recess in the metal that is usually greater than the width of the part.

Metals:
All Metals that come in roll form

Tolerances:
+/- 0.002” on lineal dimensions: +/- 0.001” on hole diameters

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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).

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