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Topics - Aardvark

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1
Vetrics / Increasingly rougher cuts
« on: June 11, 2024, 10:51:51 PM »
There was a time when I used a 1/4" downcut bit and the edges of the cuts were very very clean. This was with baltic birch.
Lately I've noticed a rougher look, even with a new bit.

The spindle sounds and looks normal.

So I'm wondering, is this just the batch of baltic birch or am I missing some CNC maintenance related things maybe in order to keep the operation smooth?
One time the collar of the Spindle got 'stuck' on a cut out piece of baltic birch. The run finished without interruption, but there was some 'wood burn' on that collar which indicated force on that wedged piece of ply. Just mentioning this in case that's relevant information.

Thanks!
Albe

2
Help and Support / Y-axis keeps getting stuck
« on: October 24, 2023, 02:54:24 PM »
I just finished a cut with my CNC. When it wanted to return to the workpiece origin, it seemed stuck in the Y-axis direction. When I wanted to move it manually along the y-axis, it kept getting stuck while making a higher pitched motor sound when stuck. Homing it works, because it moves slowly, but when I move it on the fast setting, it keeps getting stuck, in random locations that are not consistent. Some information on the last run:
1/2" end mill with cuts being up to 2" deep in multiple steps. The bit didn't get hot, everything worked great. What I couldn't use was the dust collection, because the cuts were so deep. So since there was a lot of hogging out, there are a lot of shavings everywhere.

I checked the gear track, which is underhung and therefore protected from dust and shavings and I can't seem to identify why the machine keeps getting stuck. There's nothing blocking it. What am I missing? Is there a proximity sensor somewhere that might be caked in dust? Turning the machine OFF and ON again doesn't fix it...

Thanks for your help!

Here is a video: https://drive.google.com/file/d/1HClh39fgXhKAHIa_UPY9SG8BG6E1yA4s/view

3
Help and Support / snapped 1/4" compression bit on 15mm Baltic Birch
« on: April 23, 2023, 11:15:12 PM »
I'm wondering if someone has some insight. I'm using a 1/4" Whiteside UD2102 compression bit to cut 15mm Baltic Birch. Some guy on youtube recommended to run the first cut of a profile toolpath at 0.28" deep. This guarantees that the downward spiral is cutting along the surface, not the upward spiral, which would create ugly tear-out.

So I've been running 3 sheets without problems and then during the 4th sheet the bit snapped. The snapping wasn't very dramatic, I didn't even notice that the bit was laying on the table, only then when I realized the cutting got so quiet.

Now I'm trying to troubleshoot how to prevent this from happening. I'm not sure whether it happened during a profile path or a pocket.

Profile toolpath parameters:

Spindle Speed 15000rpm
Feed Rate 100 in/min
Plunge rate 10 in/min
Chip load 0.0033 in
Pass Depth 0.1578" (except first pass is at 0.28")
Stepover 40%

Pocket toolpath parameters:

Spindle Speed 15000rpm
Feed Rate 100 in/min
Plunge rate 20 in/min
Chip load 0.0033 in
Pass Depth 0.2362"
Stepover 50%

All cuts are very clean and the bit literally stays at room temperature and doesn't heat up (I carefully touch it at the end of each run..). It does get loud however, like a higher pitched screetch. Is this normal for a compression bit? The Upcut bit didn't make such a sound. Actually more so for the first cut of the Profiles, the Pocket cuts are not quite as loud. There are no burn marks whatsoever, very clean cuts! I mean how else am I supposed to cut the Profiles while taking advantage of the compression bit...the first cut kinda has to be at least 0.28", right? :-\

My suspicion is that the Stepover for the Pockets is a bit too aggressive maybe, generating too much force perpendicular to the bit, or generally the feed rate is a tad high? What do you think?




4
Help and Support / cutting thick material
« on: April 09, 2023, 08:43:45 PM »
This might be a newbie question.
I would like to cut material that is let's say 3" thick. Now I'm wondering if I can do this with my regular 1/4" bits with specified 1.5" cutting depth or if I need to get a super long straight plunge or endmill bit.

Of course I'm planning on doing a lot of shallow cuts, not deeper than 50% of the tool diameter. I've noticed that some CNC flat endmill bits can have a slightly smaller tool tip diameter than the shank, for example 0.248" at the tip and 0.25" at the shank. Now let's see I'll be using this bit, set it in the collet in a way so that the collet won't hit the workpiece during the deep cuts (but deep enough so it won't create runout). As soon as I start cutting deeper than the bit specification of 1.5", won't the shank which is a bit thicker start rubbing against the material and create problems? This is my main concern.

Basically I'll need a bit whose true tip diameter is larger or at least equal to the shank diameter. Would for example the Amana tool RC-3200 be appropriate here?
To sum up the question: what's the easiest way to cut a 3" deep profile toolpath?

Thanks!
A

5
Help and Support / Vacuum table strength SCV44
« on: March 29, 2023, 10:02:25 PM »
Ok, so I prepared my 3/4" MDF spoil board by taking off 1.2mm on each side and then sealing the edges with a 60/40 wood glue/water mix.

Then I went ahead and ran my first project!

I processed some 15mm 4ft x 4ft baltic birch ply, which got held down really nicely by the vacuum through the MDF.  As the machine was cutting close to the home position (the 4x4 plywood sheet still in one piece) I noticed that suddenly the sheet came off the vacuum table by bending upwards. I quickly pushed it back down and it continued to hold, even though for these hot 2 seconds the cuts ended up being too deep.
I set up my vacuum table by assembling the pump properly (I think). Vacuum table goes through filter into pump inlet and then on the pump outlet is the muffler.
It almost seemed as if the strong suction of the dust collector was counteracting the vacuum table, pulling the workpiece up in the corner. Could this be??

Also, when the workpiece sheet is about 1ft x 1ft in size, the holding power does not seem to be enough to set up profile toolpaths without tabs. Is this expected, that with this size I really have to use tabs?

6
Help and Support / Pneumatic rollers odd behavoir
« on: March 29, 2023, 09:42:34 PM »
Hey there,
my rollers behave in way that doesn't make sense to me. I can lift them with the K1 and K2 buttons, but when I start a job close to the home position (X=,Y=0), only the second roller stays up and the first one goes down. I cannot lift the first one up again, the pendant indicates that it registers me pressing K1 by illuminating that section blue for a short time, but it stays down. Then after the first roller crosses the lower green line (see image), it goes up. The second roller has the same problem, but at the other end of the table.

In other words, as soon as the respective outer rollers cross the green line, they go down or up suddenly without being instructed to do so.
It creates the problem that when the machine is moving from the outside back to the center of the workpiece, one of the rollers runs against the vacuum table and the motors complain and loose their position.
???


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