2014-09-28 12:26:00
#1
Does anyone have experience with SMMA molding?
Looking for expert advise on screw types, typical injection pressures, risks and general process knowledge.
2014-09-28 05:44:00
Top #2
type xloay and ask them for same its more faster
2014-09-28 08:06:00
Top #3
my experience in SMMA is with gas assisted injection moulding...
2014-09-28 10:40:00
Top #4
Thanks both. Any special considerations required? (mold & hotrunner maintenance, dryer/hotrunner/barrel temperatures, residence times, ...)
2014-09-28 13:11:00
Top #5
I have had experience with SMMA and PMMA for many years. This resin is typically hydroscopic and needs to be dried ( 72 deg C for 2 hours ). You want a resin melt temperature of about 220 deg C with a mold temperature of 50 deg C. As SMMA is an amphorous material you need a short L/D barrel similar to what would be used with an ABS.
2022-07-15 17:04:24
Top #6
A couple of items on SMMA:
1) NEVER, NEVER run it wet or into a mold that is sweating as any moisture added to the melt can eat hot runners and molds.
2) SMMA typically needs very little pack/hold time. Run your gate freezes studies!
Injection pressures will be very high as it normal pushes very hard. Do not run over the manufacturers recommended melt temps in order to fill the tool. If your having filling problems, open up the gate thickness and runner diameters.
Machine screws design can be general purpose or low compression but don't use a high compression "pumping" screw.
1) NEVER, NEVER run it wet or into a mold that is sweating as any moisture added to the melt can eat hot runners and molds.
2) SMMA typically needs very little pack/hold time. Run your gate freezes studies!
Injection pressures will be very high as it normal pushes very hard. Do not run over the manufacturers recommended melt temps in order to fill the tool. If your having filling problems, open up the gate thickness and runner diameters.
Machine screws design can be general purpose or low compression but don't use a high compression "pumping" screw.
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