Fabricating Makrolon® GP polycarbonate sheet.

Circular Saws
A circular saw blade with carbide teeth utilizing the “triple chip” tooth design is the preferred method of cutting MAKROLON® Polycarbonate Sheet. Table or overhead panel saws are normally used. Circular saws should be run in the speed range of 6000-8000 ft/min. Blades for cutting 3/32? and thicker material should have 3-5 teeth per inch. The hook or rake angle should be 10°-15°. When sawing thin-gauge MAKROLON® Polycarbonate Sheet, it is important to have a good

supporting edge on the saw table with minimal gap between the saw blade and table supporting edge. Be sure tabletops are smooth and free from projections that might scratch or mar MAKROLON ® Polycarbonate Sheet.

 

Cicular Saw Troubleshooting

PROBLEM: Melting or Gummed Edges

SUGGESTED SOLUTIONS:

1. Increase blade tooth size

2. Reduce saw speed

3. Increase feed rate

4. Use air to cool blade

5. Use blade lubricant compatible with

MAKROLON Polycarbonate Sheet

6. Inspect blade for sharpness

7. Check blade-fence alignment

8. Reduce number of sheets in stack

PROBLEM: Chipping

SUGGESTED SOLUTIONS:

1. Decrease blade tooth size

2. Increase saw size

3. Provide better clamping and/or support for sheet stack

4. Reduce feed rate

5. Check blade and arbor for wobble

6. Inspect blade for sharpness

 

Band Saws

Band saws are useful for trimming formed parts or irregular shapes. Band saws should be run at 2500-3000 ft/min and have 8-12 teeth per inch. Coarser (larger tooth) blades perform better with thicker gauge MAKROLON® Polycarbonate Sheet. Proper support of the part to be trimmed is important because vibration may induce cracking if the cut is not smooth. Sanding the edge

smooth after cutting is recommended.

 

bAND SAW TROUBLESHOOTING

PROBLEM: Melting or Gummed Edges

SUGGESTED SOLUTIONS:

1. Increase tooth size

2. Reduce saw speed

3. Use air to cool blade

4. Check blade sharpness

PROBLEM: Chipping

SUGGESTED SOLUTIONS:

1. Decrease tooth size

2. Slow down stock feed rate

3. Provide better clamping and/or support

to eliminate vibration

4. Check blade sharpness

 

ROUTING

Routing produces a smooth edge on MAKROLON ® Polycarbonate Sheet and may also be used to cut curved or irregular shapes. Routers with a speed of 20,000 to 25,000 rpm are preferred. Use straight (fluted 2 or 3) carbide-tipped or high-speed steel router bits. Bits should be 1/4? to 1/2? diameter for best results. Use a router with at least 1 H.P. motor. Special care must be used when routing–Use proper guarding and eye protection. Stock feed rates must be monitored closely. Feeding MAKROLON Polycarbonate Sheet at excessive rates can cause vibration and cracking. It is important to feed the sheet against the rotation of the router bit and to provide a fence for sizing when making straight cuts.

 

LASER CUTTING

MAKROLON Polycarbonate Sheet can be cut using industrial cutting lasers. Edges may become amber or brown when laser cutting. For information on laser cutting equipment and part cutting services, contact the manufacturer of your equipment or the suppliers listed on this page.

 

SHEARING

MAKROLON Polycarbonate Sheet may be sheared using a conventional sheet metal power shear. It is important to adjust the top blade clearance in relationship to the bed blade. A clearance of .001? is desirable to avoid a rough edge cut. Shear single sheets only.

 

Die CUTTING

Die cutting MAKROLON® Polycarbonate Sheet in gauges up to .080? thick is normally achieved utilizing the following steps. Steel rule dies mounted in a press provide good results. The shear strength of MAKROLON Polycarbonate Sheet is 10,000 psi which is appropriate for die cutting methods. Calculating the required press tonnage to cut MAKROLON

Polycarbonate Sheet:

 

     F= P x A

     2,000

     F= Required force in tonnage of the press

     P=10,000 psi (shear strength of MAKROLON

     Polycarbonate Sheet)

     A=The sectional area to be cut

 

Example: Die cut 12? x 20? x .030? thick rectangle

Total length of cut = 20? + 20? + 12? + 12? = 64?

Shear area = Total length x thickness (.030?)

                       or 64? x .030? =1.92 in2

 

Required force = P = 10,000 psi

 

     F= P x A = 10,000 psi x 1.92 in2   = 9.6

       2,000              2,000 lbs.

 

Press tonnage (PT.) = 9.6

 

Use 3 PT. (.042?) thick steel to fabricate steel rule die. Flush or center bevel ground rule provides a clean cut. Facet ground steel rule is used to cut thicker gauge MAKROLON ® Polycarbonate Sheet (above .060?).Be sure platens are parallel and that the backup pad is in good condition. Backup pads can be made from a wide variety of materials such as nylon, HDPE, etc.

 

Drilling

MAKROLON Polycarbonate Sheet is easily drilled using ordinary high-speed steel drill bits. Regulate pressure and speed until a continuous spiraling chip is observed. Use air or water as a coolant if required. Using cutting oils may cause crazing. Be extremely careful if using taps or self-tapping screws; tapping creates notches that can result in stress cracks because polycarbonate is a notch sensitive material, like most clear plastics. Recommended drill speed is 350-1750 rpm.

Hole Diameter

Drill Speed (RPM)

1/8”

1750

1/4”

1000-1500

1/2"

350-500

Article Title:
Fabricating Makrolon® GP polycarbonate sheet.
Article Summary:
Cutting, Drilling, and Machining information
Article Date:
6/5/2008
Article ID:
445
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