Even if it & rsquo; s a material you have excellent with, double-check data sheets for the resin supplier & rsquo; s melt-testrature recomingations.
Target maket testure. If it is a resin or grade new to you, check to see what the manuoFacturer recommends.
Fig. 1 Shown Here are the four basic barrel zones on an inition molding machine that must be set up properly, along with the nozzle body and tip.
: Let & rsquo; Say It Recommends 450-510 f (230-265 C) for a semi-Crystalline Resin. Pick some near the center, in this case 485 f (250 c). You now have the target testNext is setting up the barrel zone propile.
Process. In my Experience, Backpressure is Stated Incorrectly in 95% of Resin SUPPLIERS & RSQUO;
Real World, However, Such Designs Are Common.
Fig. 2 Typical Molding Machine Screws Consist of Three Sections, as Shown Here.
A screw is composed of three section (fig. 2):
In theRE IS Air Between them. This Air Needs to Vented Out the Feed Throat or IT Will Cautry Privems SUCH As SPLAY.
2. The transition/compression zone. This usually comprises 25% of the scream.
3. The Metering Section. This Also is typically 25% of the scream.
SEMI-CRYSTALLINE Resins Melt Very Differently From AMORPHOUS ResIns.
LB. Bottom Line: It is Harder to Properly Melt a semi-Crystalline Resin.
So Both Screw and Resin Characteristics Must Be Taken Into Account When Setting Up Barrel Zone Temperatures. How does one sort all this out?
not cause briding.
. Thus, if the shopping is a large portion of the barrel capacity, I set the rear zone high, Perhaps 490 f (255 C). If the shot is les than 40% of the barrel, the rear zone would, 4666666F (240 C), to ensure there is no metalt formed in the feed section to block vennting. For an amorphous resin I do not raise the rear zone.
Seconds. If the front zone is a different testness than the melt, some portion of that cylinder of the platic will be at a different testure, as the as a pointic is a poor head confctor.
Avoid the & lsquo; quagmire & rsquo; in setting up nozzle testures.
Injecting Mold Manufacture from the target and adjust the setpoint academy.