Adding plastic/ removing from mold

I have a part that I need injection molded but will still require some edits. I’m planning on soft tooling to start. I’m planning on using thin wall thicknesses and as need be thicken them up. Its easier to remove material from the mold and add more plastic than the opposite correct? I can never remember this part.


Metal safe = add plastic.

So yes, adding plastic is easy. Removing plastic requires adding material to the mold, usually by welding.

And as a rule of thumb it is easier to remove mold material from the core side instead of the cavity side.

Ok thats whats what I thought. What do you mean by metal safe = add plastic?

thanks again

What he means is the equation to be metal safe, add plastic to part - metal safe = add plastic.

By adding thickness to your part, you will be machining metal away to accomplish it. The converse is true - to make thinner walls or removing a plastic feature, you will need to weld, fill, grind and re-finish the mold to fill in the area you want removed from the plastic.