Pla printed part question

[gorf26]

I have printed some parts with pla and they have a 10mm hole for a liner rod...

I have tried everything but the rod always seem to bind or get tight towards the center of the part and I have to pound it in but I need it to be able to slide. I have drilled and also reamed the hole but still tight in middle any suggestions?

thanks gary

[S3D-Chris]

Can you post your factory file?

[wirlybird]

This is not unusual for FDM type printed parts.

If you are designing the part you will need to make the hole slightly larger than the actual size needed.
For smaller holes I may add about .2mm to the hole size but usually I will have to drill them out a bit for a good fit.

The smaller the hole the more pronounced this under sizing will potentially be.

[gorf26]

Yes I will post it, its been a while since I printed it so I will have to find it..

I did drill out the holes, and the 10mm drill went all the way thought ok and so did a 10mm reamer but still tight when rod reaches about mid way into part.
Should I try a 11mm drill I don't want it to loose either.

Thanks gary

[airscapes]

Put the rod in the drill and work it in an out of the hole.. Don't run it too fast as the heat from friction will cause the pla to get soft quickly.

[shrop_pat]

Is the rod 10mm ?

[SteveYYC]

Is the rod straight? if you have a bent rod in a straight hole (or a straight rod in a bent hole) it will go in in for a bit and then bind somewhere in the middle.

After inserting the rod in the hole check if it's pressed against one side of the hole. If you turn the rod and it gets pressed against different spots on the edge of the hole as you rotate it thats a good indication the rod is bent or the hole follows a curved path (something that can happen if you're running a delta).

If the rod doesn't need to be held close by the entire hole you could change the geometry of the hole to be the correct size near the openings, but you could widen it out by a bit in the middle where you feel it binding.