What’s Causing These Marks

[BruceR]

Can anybody tell me what causes these tramline marks between passes? The chamfer is a 32mm V bit and the profile a 4mm end mill. Both are leaving marks. I’m not sure what I’ve done. I’m pretty sure this is a recent thing.
Thanks for your help.

[JAZZCNC]

Hi Bruce,

You haven't knicked the cutting edge have you, those marks on the chamfer look like the blades have hit a nail or something in the material.?
It's hard to see on the sidewalls because it just looks like grain tear.

[BruceR]

Thanks Dean. I don’t know. It happened with both tools. It’s caused a little groove on the chamfer between passes. I only had the piece heat glued down. I wonder if it was moving? It looked solid.

[RobC]

I get them on passes like such, if you are not able to solve the issue leave a radial rough cut at say 0.1mm and come back with a finish pass at full depth to clean them up.

[BruceR]

Thanks Rob. I’ll do a small project on Monday and do a final pass. Thanks for your help.

[JAZZCNC]

Thanks Dean. I don’t know. It happened with both tools. It’s caused a little groove on the chamfer between passes. I only had the piece heat glued down. I wonder if it was moving? It looked solid.

Could be a number of things but yes if it was shifting about from tool pressure that would cause something similar but if it keeps happening you have my number give us a ring and we'll help you work it out.
The suggestion from Rob to leave material for a finish pass is a good idea and nearly always gives a nicer finish and something I would recommend on anything you want a good finish or if hard or fluffy stringy material.

[routerdriver]

I'd like to see a plan view image.My initial suspicion is either a tool length discrepancy or a slight tramming runout.It seems a bit odd that the spacing of the marks looks quite evenly spaced as the cut proceeds down.The suggestion to leave a little material for a finishing pass may well be enough to eliminate the problem.

[BruceR]

Thank you. I’ll have another look at it. It’s a pain. It doesn’t look much but it means I need to do a lot of sanding and it didn’t happen before. Thanks for your help.