Sawing
Circular saws, band saws and jigsaws can be used to cut sheets extruded with Bayblend ET1000 resin. Some tooth set will prevent binding. However, too large a set may result in surface roughness. For typical conditions, standard saw blades were found to yield good results based on visual evaluation of quality.
When using a jigsaw, keep the feed rate slow and the pressure light, and
hold the part firmly. The reciprocating action of a jigsaw makes it difficult
to control cooling, feeding and pressure. Choose blades with generous set
to minimize friction. Most Bayer plastics have been successfully cut with
standard jigsaw blades operating at 875 cycles per minute.
Band sawing, the preferred method for plastics, can cut contoured or irregular shapes in addition to straight lines. As rules-of-thumb:
- Use precision or standard blades for thin parts;
- Use buttress or skip-tooth blades for wall sections greater than 1/8 inch;
- Choose band saw blades with a generous set to reduce friction and heat buildup;
- Cool the cut junction area with air or a water mist;
- Control the feed speed carefully to prevent binding or gumming; and
- Use saw guides whenever possible.
Table 3 - Band Saw Conditions
| Part Thickness (in) | Tooth Type | Pitch (teeth/in) | Band Speed (ft/min) |
| < 1/8 | Precision or Standard | 8 - 12 | 2,000 |
| 1/8 - 1/4 | Buttress or Skip tooth |
5 - 6 | 1,500 |
| >1/4 | Buttress or Skip tooth |
3 - 4 | 1,000 |
Table 3 lists suggested band saw speeds and configuration for most Bayer MaterialScience grades, including Bayblend ET1000 resin.
Circular sawing is usually used only for straight cuts. Circular saw blades for plastics should be hollow-ground with slots provided for blade expansion and cooling. The required blade pitch depends on the diameter of the blade. A larger blade size and greater plastic thickness reduces the optimum pitch value. A four-inch blade for thin sheet should be 8 to 10 teeth per inch for most plastics. The pitch can increase to about 6 to 8 inch for 8 to 10 inch blades used on sheet thicker than 1/4-inch.
As a general rule, use the highest pitch value that gives the desired results.
