Sprue Cutting

Hello, I am making an injection molding machine and I want to have as big of a nozzle as possible, but I am wondering if I will be able to cut the sprue so that it is as flat as possible (sprue is that little piece of plastic that stick up from the hole in the mold). I dont want to go too big with the nozzle and then be left with a huge mark on my part, any suggestions?

The usual way to get round this problem is to use a ‘gate’ between the actual part and the sprue or runner. The gate is a small narrow usually flat channel and the part can be easily snapped off later. If any cleanup is required this can be done by sanding or with a file.

Ok thanks for the info, I might just use a stepped bit and only Drill half way in, and then just get a micro file and square it out so the nozzle will fit in the big hole and the plastic will flow through the square one.

Not sure what happened, two (identical) pictures eventually came up so I deleted one. I got an error something like “slow down you’re too fast!”

hmm should work @andyn, you get an error or something?

(trying to post a picture but it keeps disappearing)

picture