MACHINING INFORMATION FOR SUCCESSFUL

MACHINING INFORMATION FOR SUCCESSFUL

FABRICATION OF POLYMER CORPORATION DURASPIN™

Duraspin™ roller tool parts perform under conditions that are normally considered too harsh for thermoplastics. With a continuous use temperature of 450' F, Duraspin roller tools maintains superior strength and stiffness at elevated temperatures and excellent chemical resistance.

Duraspin roller tool grades are machined using similar techniques normally used for metals. However, because Duraspin grades are very abrasive to standard and high speed tools, it is recommended that carbide-tipped tools-or preferably, diamond-tipped insert cutting tools are used. Diamond tipped ones will out-last carbide tools and provide strong economic incentives.

When Machining Duraspin™ roller tools

Remember ...

* Thermal expansion is approximately 3 times greater than steel

* Plastics lose heat much slower than metals

* Plastics operating temperatures are lower than metals

* Plastics are more elastic than metals

Because of these differences, you may wish to experiment with tool materials, tool angles, speeds, and feeds to obtain optimum results.

OTHER MACHINING TIPS

* Thin sections and sharp corners must be worked with care to prevent breakage and chipping

* Positive tool geometries with ground peripheries are recommended

* Carbide, insert or diamond-tipped tooling with polished top surfaces should be used

* Use adequate chip clearances to prevent clogging

* Properly support the material to prevent it from springing away from the cutting tool

COOLANTS

* Coolants are not required, but may be used for optimum finishes or close tolerances

* If coolants are used, a spray mist water solution oil is recommended

* Pressurized air or vacuum is commonly used for chip removal and as a light coolant

TURNING

Depth

Of Cut

Speed. Feet/Min

Feed. In./Rev

.025 in deep cut

300-800

.004-.025

When machining plastics, positive geometries with ground peripheries are recommended. Ground peripheries and polished top surfaces generally reduce build-up on the insert and improve surface finish. A fine-grained C-2 carbide, insert or diamond-tipped tooling is generally recommended for these operations.

When cutting off, it may be necessary to chamfer the I.D. before cutting to prevent the material from chipping out.

DRILLING

Nominal Hole Diameter	Feed, Inches/Rev
1/16"	.007-.015
1/8"	.007-.015
¼"	.007-.015
½"	.015-.025
¾"	.015-.025
1"	.020-.050
1-1/2"	.020-.050
2" or larger	.020-.050

High-Speed Steel (M10, M7, M1)

Speed, Ft./Min 150-200

Important Note: Large Diameter Holes

A slow spiral (low helix) drill or general-purpose drill ground to a point angle of 118° with a lip clearance of 9° to 15° is recommended. In both instances, the lip rake should be ground off (i.e. dubbed off) and the web thinned.

Drill a small (max ½" diameter) hole at a speed of 600 to 1,000 rpm using a positive feed of approximately .005" per revolution. Avoid hand feeding the drill because "grab" can occur and stress or cracks may develop. A secondary drilling at a speed of 400 to 500 rpm is required to expand the hole to 1" diameter.

END MILLING - SLOTTING

High Speed Steel (M2, M7)	Depth of Cut	Speed Ft./Min	Feed. In./Tooth
¼"	.250	270-450	.002
½"	.250	270-450	.003
¾"	.250	270-450	.005
1", 2"	.250	270-450	.008
¼"	.050	300-500	.001
½"	.050	300-500	.002
¾"	.050	300-500	.004

*High spindle speeds and fast table travel are possible with adequate holding fixtures

FACE MILLING

Depth of Cut

Speed Ft./Min

Feed

In./Tooth

.035

500-800

.006-.035

*Either high positive or high shear geometry cutter bodies are recommended

SAWING

Material Thickness	Tooth Form	Pitch Teeth/In.	Band Speeds Ft./Min
>1/2"	Precision	8-14	5000
½"- 1"	Precision	6-8	4300
1"- 3"	Buttress	3	3500
3"	Buttress	3	3000

* Band sawing is versatile for straight, continuous curve, or irregular cuts

* Table saws can be used for thicker sections

* Rip and combination blades with a 0°-tooth rake and a 3-10°-tooth set are most common

* Hollow ground circular saw blades without set give smooth cuts up to 3/4"

* Blades with a set are sometimes used to reduce frictional heat

POLYMER CORPORATION ENGINEERING PLASTIC PRODUCTS

2120 Fairmont Avenue

P.O. Box 14235

Reading, PA 19612-4235

Telephone:

(800) 366-0300

(610) 320-6600

Fax: (800) 366-0301

In Canada:

495 Laird Road

Guelph, Ontario NIG 3Ml

Telephone:

(519) 837-1500

Fax: (800) 265-7329

™Duraspm is a trademark of Polymer Corporation

All statements, technical information and recommendations contained in this publication are represented in good faith, based upon tests believed to be reliable and practical field experience. The reader is cautioned, however, The Polymer Corporation cannot guarantee the accuracy or completeness of this information and it is the customer's responsibility to determine the suitability of Polymer's products in any given application.