CNC FREAK Posted May 20, 2014 Report Share Posted May 20, 2014 i have a small problem with a twister moldthe U-shaped ribs of the body are not completely filled with plastic.when i inject fast i have this problem, i guess air is closed in so i inject very slow, the result is better but the problem is not solved.Dont know how to solve this problem...The injector hole is 5/8, the conical shape of the injection channel on the drawing might not be perfect for a 2 color laminate. Done some tests and the colors are mixed up. Does anybody know how to get the bodys FULL with plastic ? Thanks ! Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted May 20, 2014 Report Share Posted May 20, 2014 (edited) I've been doing alot of molds with ribs lately.... two things I've learned... 1. Place a vent at EVERY rib top and bottom. They can be VERY small and even cut in by hand if necessary - a .005"-.0075" deep vent is plenty. On my molds I try to run .005 deep with a 1mm dia ball mill. 2. If you can run the body "horizontal" in the mold and fill from the top - it may help. This allows the air to rise up and out of the vents and not get trapped perpendicular to your vents. So if you took you're injection sprue and rotated 90 degrees CW I'd think you'd have a much better chance to let the air escape. J. Edited May 20, 2014 by SlowFISH Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted May 20, 2014 Report Share Posted May 20, 2014 i have a small problem with a twister mold the U-shaped ribs of the body are not completely filled with plastic. when i inject fast i have this problem, i guess air is closed in so i inject very slow, the result is better but the problem is not solved. Dont know how to solve this problem... The injector hole is 5/8, the conical shape of the injection channel on the drawing might not be perfect for a 2 color laminate. Done some tests and the colors are mixed up. Does anybody know how to get the bodys FULL with plastic ? Thanks ! twistermold.jpg Out of interest, how big is that grub? 1 Quote Link to comment Share on other sites More sharing options...
CNC FREAK Posted May 20, 2014 Author Report Share Posted May 20, 2014 (edited) hi slowfish thanks for the FASTresponse -> fastfish understand about the vents, i'm going to try that !i inject each bait seperately vertical because i wanted to make perfect 2 color laminates At the moment i have 2 twisters in one mold, using the blending block i inject the 2 baits seperately. i could inject these horizontaly and inject from the top, that should work also for laminates but i think, if i want to have perfect laminates i can only inject one bait at a time.Possible to make a multi cavity laminate twistermold ? i think the plastic will be mixed up.... Edited May 20, 2014 by CNC FREAK Quote Link to comment Share on other sites More sharing options...
gone2long Posted May 20, 2014 Report Share Posted May 20, 2014 Save yourself some grief and time, I'm in no way saying copy another mold makers design but they have these types of generic questions resolved by trial and error so let their hard work assist you in resolving some of your issues. Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted May 21, 2014 Report Share Posted May 21, 2014 I've shot a few multi cavity lures with a blending block that had a layout of the injection sprue from top and a horizontal layout to the bait. I agree it's a much tougher deal to get perfect baits - but if you make sure you line up your blending block in to the mold just right you should be good to go... but I agree it's not much fun!! I am working on a lizard mold that I laid out the same way your worm is for exactly the same reason (Laminating)... can't get rid of air in the body ribs which are very deep.... even tried shooting it at a 45 degree angle in my vice and still get air pockets.... Pretty sure getting those ribs "vertical" with a good vent is the key... I'm in the process of filling the original sprue and cutting another at a 90 degree angle. J. Quote Link to comment Share on other sites More sharing options...
Frank Posted May 21, 2014 Report Share Posted May 21, 2014 With those ribs I agree a 90deg will be your best bet. As for laminating a multi-cavity mold with all things being equal like temp and pressure on the injectors it will work great. I do it all the time. You see it is a hydraulic thing. As long as nothing is in the way it will just move along and not mix. Slowfish if you can round over the top of the ridges of the ribs. Plastic flows better over rounded corners than square ones. This should help a lot on trapping air. Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted May 21, 2014 Report Share Posted May 21, 2014 With those ribs I agree a 90deg will be your best bet. As for laminating a multi-cavity mold with all things being equal like temp and pressure on the injectors it will work great. I do it all the time. You see it is a hydraulic thing. As long as nothing is in the way it will just move along and not mix. Slowfish if you can round over the top of the ridges of the ribs. Plastic flows better over rounded corners than square ones. This should help a lot on trapping air. Thanks for the tip Frank.... I also made a bit of a design/tactical error with the ribs as I was getting a bit "creative" with the baits form.... I tried "curving" them across the body (think C shapes instead of straight ribs/lines).... it looks AWESOME but I'm pretty sure the curve I put on them is what's trapping the air... probably why nobody else is doing it!!! LOL!!! But I'm gonna keep screwing around with it to see what I can get out of it... who knows, maybe I learn something that makes it all work. J. Quote Link to comment Share on other sites More sharing options...
