General Description
An amorphous thermoplastic developed as an alternative to ABS, but with improved weather resistance, and widely used in the automotive and building industry.
Pre-Production
ASA is mildly hygroscopic, so drying may be necessary before processing. It is best to dry all ASA for 2-4 hours at 80ºC-85ºC. When using hopper driers, the temperatures can be increased to 90ºC to ensure that the material is sufficiently dry prior to being moulded. If a circulating air oven is used, then dry for 2 hours at 80ºC -85ºC.
Temperature ºC
Zone No.
Location
From
To
1
Hopper Throat
50
60
2
Barrel Rear (hopper end)
210
230
3
Barrel Middle
230
250
4
Barrel Middle
240
280
5
Barrel Front
240
280
6
Barrel Nozzle
240
280
7
Mould
40
80
Processing Notes
Injection speeds as high as possible as this gives the best surface finish and the strongest weld lines Medium to high screw speeds are possible as ASA can withstand high shear stresses Back pressure should be kept as low as possible Avoid long residence times at temperatures above 280ºC.
Tool Requirements
- Typical shrinkage values range from 0.4% to 0.7% with negligible after shrinkage.
- Venting must be good as high injection speeds are recommended.
- To achieve a high surface gloss on the moulding, the finish of the cavities and cores must be excellent and fault free.
- If the moulding starts to distort upon ejection, both halves of the mould can have their temperatures set independently to help counteract this.
- Tool temperature variation will likely be limited by the higher temperatures required to get good surface finish on visible surfaces.
Post- Production
Shut off heat and purge the barrel clean – no need to purge with another material due to the risk of contamination. Purging with another material is best avoided.
Portfolio
Chimei- ASA- Kibilac
