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Part molding creating into ejector holes

Tesla77

New member
When I create my part molding it is creating into all my ejector pin holes. I tried creating the ejecor pin holes in the mold cavity using clearance cut and just plain cut out. I can't get it to go away. Before the ejector holes are added the molding is perfect. Runners and all part detail are fine.
Edited by: Tesla77
 

Tesla77

New member
Yes, this is after all mold splits. I am working in Mold Layout. Ejecor pins and the water network are my last steps in the design.
 

Moroso

New member
I brainfarted on this one



When it creates a Molding it's copying all the surfaces that are open and closies them up an solidifying the part.


WhatI do is i create a Component Display or Style of just the part I'm molding on the screen, once I Extract all the parts for my mold design I then do a Molding so only the voids are the part area itself. Once the Molding is created then I shade the parts with different colors to see ifI missed anything


If everything looks alright I delete the Molding


HTH


Brian
Edited by: Moroso
 

BMD

New member
Why wouldn't you either do the molding before adding ejector pins or get in front of them to do the molding?


I don't normally do a molding. I don't see much use in it except maybe for fixtures for second operations.


What do you get out of making one? I'm not being a smart *ss, I'm interested in what value you see in it to see if it would be ov value to me as well.
 

Tesla77

New member
The reason why a molding is important is to check runners and molded part(s)for errors. Or to have a total full molded part file.And as Moroso replied you are able to check for mistakes in your total design. If you need to build secondary fixtures such as gate mill fixtures, it is very valuable. It's up to you if you think it is of value to you.


My problem is that when I add my ejector pin sets and do a cut out to the mold insert I am getting along with my molding the ejector pin holes. I don't know what's causing this to happen.
Edited by: Tesla77
 

BMD

New member
Tesla77,


I can see wanting to check to runners and gates on a designed performed by a subordinate, but I know what runners and gates I put in the design and can check them by looking at the solid models of the assembly and tool components.


I also know what my molded part file looks like because it is the part I split with. I have already checked the part for drafts ect. prior to splitting.


I can see using a molding if you need to build fixturing for degating a part that is not degated in the tool. I just can't imagine the extracted components not producing an exact replica of the part used to split the tool.


As far as your ejector pin holes, I model ej pin holes nominal and let the shop deal with clearance so the part should not fill the holes. If you design clearance into the holescould youget in front of the holes and create a seed and boundry surface of the parting line to keep them closed when doing your molding?
 

Moroso

New member
Molding is a direct result of the tool geometry, not of the ref model.


I mostly use it to check for areas I forgot or differences that I have to put in the tool for tooling problems
 

BMD

New member
Moroso,


I appreciate what you are saying but my tool geometry is a direct reslut of my ref model. I make no changes to part geometry in the tool. If needed I modifiy the ref model and get it approved by the customer before splitting.


I have had more errors or mistakes in tool designs than I would care to mention but have never had a problem with part geometry. The part geometry is ALWAYS the same as the ref model, except of coarse having a gate attached.


I may create a few moldings to see what, if anything, I am missing out on.
 

tommypurple

New member
I do create Moldings and it does have all the ejector pins and cores that are cut into the inserts. You can create a surface of the inserts before you put all the ejector pins and core cuts, and then use that surface to cut all the extra stuff off of your molding. cut using quilt is a powerful tool. I give my moldings to the flow guy to run flows on my part models with gates, etc.... good info


If that doesn't work you can go into the part and manually cut off the ejector pins... use edge/cut to surface....
 

Tesla77

New member
Thanks Tommypurple, that is what I have been wanting to know. I didn't know if it was something I was doingthat caused the extra geometry. I have been cutting off the extra geometry on the molding to solve my problem in the meantime. Thanks again!!
 

TeQie

New member
hi, just a quick question....if you cut off the geometry, does it give the same geometry (precision) for the mold?
 

BMD

New member
I still don't get it. The only use I can see for a molding is to give the molder a shot weight to set up his press. You would have to do your molding from the complete assembly file so it would include all runners and the sprue, etc.


Some of you want to use a molding to check that it matches the part file... it won't, your molding will have shrink. Do you then scale your molding to eliminate the shrink? Some of you cut off the ejector pins. How many operations do you introduce to your molding before comparing it to the part model?


Some of you run a flow analysis on your molding. Why wouldn't you run your flow analysis before you split the whole thing up? Model the gate and a short runner onto the part and run your flow. You can then incorporate the results into your split or part file.


Your moldingwill match your part file exacrtly, with shrink of coarse, unless you do something incredibly stupid. If you can't trust yourself to split a part how can you trust a molding that you have performed operations on?
 

Zaki

Member
Hy Guys
Its not this way you want to make ejector holes, if u people have EMX then u can make it in there, otherwise make all steps except ejector holes, make a new assembly and assemble all part (mold volumes) etc in there. Also make some blank parts having only datums, and make necessary names of them, then assemble all them into that assembly and merge each part with one mold volume. Now u gets the new volumes. Do all necessary modifications in those new volumes and don
 

jony

New member
if you use ej pin hole in mold layout, it will not afect your molding.


Because the system references that like a ejector pin hole and it knows doesn't afect molding.


I have done a teste and work fine.





 

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