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Injection molding Cavity sorting

Injection molding Cavity sorting

Injection molding Cavity sorting

I currently have a project which deals with an injection molding process at work.  We are molding pairs of brackets in a 4 cavity mold.  2 of the cavities are the RH bracket and the other 2 cavities are the LH.  

Currently we have a robotic arm with 2 grippers which comes down in from the top of the mold and grabs onto the sprue to remove it place it in a regrind hopper.  The 4 parts then fall from the mold into a bin which is removed for sorting when full.  

Does anyone have any ideas on what could be adapted to the end of the gripper arm to possibly allow two of the parts to fall and the other two to be picked up by the arm and moved to a different bin?  

I am not very familiar with robotics so I am not sure what can be done.  


RE: Injection molding Cavity sorting

Without knowing any more about your system, I have to guess that the robot's end effector is a simple sprue gripper of some sort.  It moves into position and the position is programmable.

Possible solutions:
(1) mount suction cups with long stroke cups to the end effector, move the end effector into position to pick the parts, then do sprue picking.  Program the arm to put parts where desired.
(2) similar to (1), but mount suction cups on pneumatic slides to provide sufficient stroke to get to the part location from the sprue pick location.


RE: Injection molding Cavity sorting

If this is a simple sprue picking robot, I would just use a vacuum generator and 2 vacuum cup/stem assemblies to pick 2 of the 4 parts. Let the other 2 parts fall along with the runner and seperate the runners. It should be easier to seperate the runners from the parts then it would be to seperate the lefts from the rights. Total investment would be around $100-$150. Well worth the money not only to reduce sorting time, but reduce the chance that lefts and rights will get mixed in the same box.


RE: Injection molding Cavity sorting

This is commonly done however it may depend on the safistication of your robot. I used to work with pressflow robots.  With the older models it was a little more difficult to do being that they had SLC150 running them. If you can not do the programming yourself the supplier of the robot should be able to help you. The molding machine set-up will also have to be changed to cut the spru then eject it and the brackets on to the end-of-arm.
Without knowing your specific equipment it is hard to advise you of the best approch to take.

RE: Injection molding Cavity sorting

Sounds like an easy task.
I think it'd be easier to switch things around so that the arm picks the parts out and lets the sprue fall. Then you could stage the arm to drop the LH parts in one box, and the RH in the other.

BTW, Tweeker, I worked with Nicolet a few years ago when working for Mold Engineering in Indianapolis. Were you there then? My name's David Sloop

RE: Injection molding Cavity sorting

If the parts are opposite of each other just put a diverter on the spru picker that sends two part one direction the other two the opposite. Build a separator under the molding area that send two of the parts to a different location.

Its a simple and cheap solution.

Family molds #*^&$%*%&~!

RE: Injection molding Cavity sorting

Look at some RoboHand, Festo, Parker, and other manufacturers grippers.  This might give you some ideas.  If we could see a picture of the parts in the mold, we can flood you with some ideas.

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