vacuum for vacuum table

For discussions related to designing and making ski/snowboard-building equipment, such as presses, core profilers, edge benders, etc.

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knightsofnii
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Post by knightsofnii »

Oh and I cut the negative shape out of a sheet of mdf, and laid that over the holes so only the spot where you put the core is exposed. beats taping everything, i know air will seep thru mdf but it works well enough.
Doug
amidnightproject
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Post by amidnightproject »

Yea Doug that's the roughing pass.

I found a 4 Flute carbide endmill (currently an upcut) works real well. Especially for Bamboo. Hardwood not so much but the 4 flute does cut through plastic better then the double I've found.

Chris gave me the idea for the tape. Works awesome. I was using scraps but It would either get in the way or never seal well enough. I pretty much just leave one side of my table taped and use it for core profiling.
knightsofnii
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Post by knightsofnii »

yea tape works the best pretty much, even masking tape does a good job.
Doug
MadRussian
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Post by MadRussian »

Before vacuum table I used double-faced tape only and the results unpredictable. DFT will cover many holes in the table, I think, make it less effective.... well DFT I got is 1 inch wide.
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
knightsofnii
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Post by knightsofnii »

i'm surprised at how well cardboard works, just unfold a few boxes, i used a beat up snowboard box to surround an old core, taped all the seams, and everything sucked down and wouldn't budge in any direction.

Easier to break down for the next job, than laying down many strips of tape.
Doug
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chrismp
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Post by chrismp »

It helps that all my cores are square. I just have a sheet of heavy plastic foil rolled up beside my vacuum table which covers most of the holes on the side of the table. Whatever holes are left open get covered by a couple of rubber sheets I have lying around. I don't use tape when I machine cores. I only use it when cutting out bases as they tend to warp and lift up from the table. As a remedy I just put tape around the perimeter of the base overlapping the base by a few millimeter. This seals the edges of the base to the table and greatly improves suction.
MadRussian
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Post by MadRussian »

Vacuum table worked. One regret I didn't do it early. Managed to pull down core and use profiling table instead of the planar
only one problem vacuums pulling to watch Amps and need dedicated at least 15 A circuit. I end up with 5 and 6.5 hp shop vacuums
For now using tape to cover extra holes.
ultimate test tomorrow. Will profile core for the first time
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
mikemigs10
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Post by mikemigs10 »

So I jumped on the band wagon and purchased a cnc mogul. I got everything hooked up and mounted to my vacuum board (which has not holes yet) MY current problem is Mach3. I am having a difficult time learning this tool. I have set my table dimensions or table limits, but I cannot seem to get a g-code to sit inside the table. Before I put the vacuum holes in I simply wanted the cnc to draw a large square inside of my table dimensions and every time I go to run the cycle it says that I exceed my soft limits. I can run a few of the g-codes that mach3 provides but others I get the same message. I know I am missing something and know I have a lot to learn but I thought I would reach out and see if anyone may have a suggestion.
ben_mtl
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Post by ben_mtl »

do you know where you are in machine coordinates ?
My first answer would be you're only "zeroing" in work coordinates so in the machine coordinates you're not within the soft limits... hence the message.
Pretty sure if you de-activate the soft limits it's gonna work, but if you have an error in your g-code you don't have the "soft limits" safety anymore.. SO I would first solve the issue.
A bad day skiing is always better than a good one at work...
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chrismp
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Post by chrismp »

Check your units! Your CAD software could be set to metric and Mach3 to imperial or vice versa.
mikemigs10
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Post by mikemigs10 »

msking some progress, thank you for the help. I checked the metrix for both programs and they were the same. I also turned off my soft limits and I do not get the message anymore but unfortunately it still isn't lined up and the machine keeps slamming up against the side. I then decided to start with a smaller rectangle to trace and that worked. Baby steps right, I am going to play around with it some more.
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MontuckyMadman
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Post by MontuckyMadman »

If the machine is crashing you dont have the zero lined up. I put all my zeros in the lower left corner for any designs i make and toolpath. Then place my material and line up my gantry, zero the machine axis'and load the file and cut.
sammer wrote: I'm still a tang on top guy.
ben_mtl
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Post by ben_mtl »

Check the axis direction, the axis "ratio" : how much the stepper has to turn to move the axis 1 distance unit.
Use the "display mode" button in the upper right corner, just below the toolpath preview, with soft limits activated it will show you your toolpath + the table limits (dashed lines) + where the tool is relative to the table limits.

If you have problems, take screenshots of mach3 (with the preview window showing the table limits) + post the code you're using to run your tests.

I too have my machine zero (home position) in the lower left corner, but actually the machine really don't care since the soft limits can be set to negative numbers. All that matters is that the software limits are matching the real world limits.
The home location is also only partially useful since when a program is run, it only cares about work-coordinates / work-origin (which are set relative to the position of the material you're cutting)
A bad day skiing is always better than a good one at work...
mikemigs10
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Post by mikemigs10 »

made tons of progress over the weekend. thanks for all the help. I am now ready to start drilling the holes for the vacuum board. I do have one question, I never double checked after watching the doneck tools video, he cuts 3/8 inch holes I have mine programed for 1/2 inch holes. Will that make a big difference in the suction? I bought a 1/2 inch bit so obviously I would have to go purchase a smaller bit.
ben_mtl
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Post by ben_mtl »

IMO 1/2" is too large.
I have 1/4" holes in a 1"x1" pattern and it's OK.
If you can, try to locate your hole pattern precisely in the machine coordinates (that means having home switches), that way you can re-use the holes from the pattern to use them with locating pins..., very helpful when combined with work offset coordinates (G54 to G59).
A bad day skiing is always better than a good one at work...
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