New set up, lines on bottom pocket.

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GJHall
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New set up, lines on bottom pocket.

Post by GJHall »

I have my machine running and thought it was set up right. Hope this is the right forum.

I tram the router, then surfaced the spoil board. The top was smooth all the way across. I set up a file for a few things,V carve and looks really nice.

I then tried a complicated one with a pocket and there were lines in some places. I know the V carving is bad, probably too deep.

I am using 1/2" MDF and screwed it down to the spoil board. I also used 2 sided tape as it seemed that it was lifting? I was using a new 1/4" down spiral end mill for the pocket. The cut was .3 deep. I also used a 1/2" 90* V bit for the v carving. Same depth as end mill.

I have attached the picture. I would send the file, but not sure if it is copyright. It is from the wounded warriors and I am trying to do this for a donation to their cause.

Any advice is greatly appreciated. I am new to routing and find it enjoyable.

Thank you in advance,

Gary
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scottp55
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Re: New set up, lines on bottom pocket.

Post by scottp55 »

Raw MDF and 2 sided tape usually have poor adhesion and allow a little lift. Perhaps a layer of dewaxed shellac/50/50 lacquer, etc and then 320G sand would improve adhesion if no gap in the tape layout. Had very good luck using Duck Brand Duct tape applied to the piece being held down(silver and says no residue for 30 days at Ace Hardware stores).
1/4" downs can generate a lot of downforce when a large portion of cutting edge is engaged,and where it dwells or slows down it can cut deeper.
My first thought is to add a 'final pass' of .015-.02" to the pocket (under "edit toolpath" and hit apply) so less force is exerted on the skim cut.
You'll need to experiment a little I think, It's usually because the material isn't Firmly down.
Sometimes because of machine flex.
Hope this helps any.
scott
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GJHall
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Re: New set up, lines on bottom pocket.

Post by GJHall »

Thanks for your reply Scott!

I will try the final pass. When I went to remove the part, the tape was holding it down pretty good. Almost had to pry it up with a knife to get it started. I am going to check the machine again before using and am going to try the final pass and see if that helps.

The lines and uneven cuts were mostly in small areas and on tight turns.

Thank you

Gary

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FixitMike
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Re: New set up, lines on bottom pocket.

Post by FixitMike »

The lines in the tight places of a VCarve cut are where the flat area cleanout tool could not reach and the program had to use the V bit to get into those areas. If you reduce the stepover on the V bit, the lines will be less noticeable. Or you can use a V bit with a flat on the tip, but then the inside corners won't be as sharp.
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GJHall
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Re: New set up, lines on bottom pocket.

Post by GJHall »

FixitMike,

Thanks for the reply. I will certainly try your suggestion as soon as I get the table back together.

Found that the Z axis is not put together properly and need to change out some bolts. Seems they think these ones were just long enough but were just a hair too long causing some issues.

Gary

GJHall
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Re: New set up, lines on bottom pocket.

Post by GJHall »

I posted another picture. If you look at the bottom right side, you can see where the end mill cut along the outside. Then you see the end mill cut the clearing of the rest of the material. It leaves a little higher than what is supposed to cut. I put a little paint on to try and make it more visible.

This is using V carve with 1/4" End mill then 1/2" V bit to do the letters. Depth is .0125 and end mill cut is .100 with 8% step over. Never got to V bit. I slowed down acceleration down 10% from last cut.

Now, on last cut, tried a 4" pocket, .3 deep. 1/4" end mill at .125 depth of cut. This was before reducing acceleration. It cut perfect. 4" accross and .3 deep. 3 passes. There was no marks on the bottom at all.

This one has me stumped. Any ideas?

This machine has to start paying for itself soon or it is gone.

Thanks

Gary
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Bottom right side

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TReischl
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Re: New set up, lines on bottom pocket.

Post by TReischl »

GJHall wrote: I tram the router, then surfaced the spoil board.
Gary

No, no. Surface the spoil board FIRST, before tramming the spindle.

If you tram to a surface that is not perpendicular to the spindle you wind up with the spindle out of tram.

[Edit: That should have read "if you tram to a surface that is not parallel to the ways of the machine....."]

So, surface the spoil board to get it "flat". It may have small waves from the cutter., but if you use a feeler block it will span the waves. Then, after getting it trammed, resurface the spoil board.

Hope this helped.

Here is a pic of why you do not tram before a rough surfacing:
Capture.JPG
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GJHall
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Re: New set up, lines on bottom pocket.

Post by GJHall »

Thanks for you r reply,

OK I will keep that in mind.

We found the Z axis has movement in it. A new one is coming to replace it.

I get so mad when suppliers don't read their own quotes.

They sent the wrong one.

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Re: New set up, lines on bottom pocket.

Post by esteeme1 »

Good call I was going to say backlash in your z axis.
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