Paco's Planing/Surfacing utility

[ryan_slaback]

So I downloaded the file opff Paco's site this morning and used it to surface a glued up panel that was too wide for my planer. On the first side everythign worked chipper. After that...

I wanted to plane the panel to .75 and if I set the 0 at the top of the panel I would not know the final thickness after machining the second side. Well, I can outsmart the code so I zeroed off the bed, raised the router to 1 and planned on taking two and a half passes each with a .1 stepdown. Should work great... Except the first move that the machine made was a plunge to -.1 It also just happened to be perfectly aligned with a screw on the rail I was using to hold the piece. Net result, one embarassed teacher and one trashed Onsrud 1.25" planing bit.

I really like the utility and the idea of planing only with the grain of the material. How is everyone else using this utility or another to plane to a designated thickness? If I would have run it in relative mode on the second pass would it have worked well?
So far I was thinking that I could also zero off the table raise to 1.000 Set that as the new Z=0 and go from there. I was curious if anybody had written a utility for planing to set thickness that took that all into account as I am a bit leary of the students repeating the exact steps that I did and forgetting either relative or rezero.

[harryball]

Ryan... entertaining story. Rest assured though, we all do things like that. For me, thankfully without the 20 kids watching.

I adapted Paco's surfacing routing but I opted to use the planer to set my exact thickness. I touch the top of the board and surface until it's flat. Then I remove the board and run it through the planer with the flat side down.

I also adapted some code, the zzero code if I remember right, to measure the thickness of a board and begin machining. You zero to the table then you use the code to touch the top of the board and you'll have your exact thickness. More importantly the bot can know the location of the top of the board for use in a program.

I could see you using something like that approach to make some code that:
- zeros to the table top
- knows where the top of the board is
- knows how thick you want the resulting board
- what your max cutting pass depth should be

With that information the code could calculate how much to plane off and in how many steps then do the job.

Not sure if that's helpful, just tyring to get some ideas stirring.

Robert

[paco]

Assuming the first surfaced side is facing the spoilboard, once you zeroed and raised the bit up to 1 inch, hit Z,Z to zero the Z at 1 inch above the spoilboard. From there, running the surfacing routine the way you did should work. Since you're starting from 1 inch thick and intend to machine off 0.25", then I would suggest to make the stepdown a divider of 0.25"... say 0.125" or 0.0625" doing it over again the needed number of time.

[knight_toolworks]

I just use v carve (newest version. make a box slightly larger then the piece getting cut) use raster and change the direction as needed. the first pass I would find the lowest spot zero and then run a tool path cutting at 0 ending at 0.
then flip it over and zero the bit on the surface and make another tool path to remove the thickness you want. with the steps you want for depth.

[mzettl]

I agree with Robert on using the planer for thicknessing, except if you have a board wider than the planer, you're out of luck. But, as Paco has already noted, you just need to zero to the table, raise to a workable distance above the desired thickness, and re-zero.

I thought of using V-Carve as well, but the problem is that it limits you to a maximum 50% stepover. Paco's program has no such limitation. If all you are doing is surfacing along the grain and not pocketing, you can set the stepover to 90% if you want, and you won't miss anything. It really speeds up the cutting time, especially on a large board as I recently did.

As an aside, this surfacing routine worked so well that I'm thinking of getting a 2" or greater surfacing bit to speed things up even more. Anyone have any experience with large surfacers?

[Gary Campbell]

Matt...
I use the Amana 2 1/2" surfacer with insert carbides. Works great for us. We use it on Domestics, Exotics and the spoilboard.
Gary

[benchmark]

Hi Paco

Would it be possible to have a copy of your surfacer utility.

Regards


Paul

[paco]

Surfacing along axis, a ShopBot routine (http://pacosarea.blogspot.com/2007/02/surfacing-along-axis-shopbot-routine.html)

[benchmark]

Paco

Thank you



Paul

[fleinbach]

I have not used Pacos surfacing program but I'm sure it does a fine job from what I've heard.

When I surface a board I simply use the Shopbot surfacing routine. It is readily available and simple to set up. Everything I have surfaced so far has been shorter then my 12' table. So to be able to cut with the grain I make the routine larger in length than the board being surfaced. Say I am surfacing a 12" X 10' board. I make by routine 12 1/2 " Y axis and 11' 1" on the X axis. I position my board 6" from the X "0" position . That way the cutter never cuts across grain. I use an overlap of 5%


The Shopbot software handles stepover the reverse of Artcam and Vcarve Pro. Maybe my mind is working wrong here but I feel the Shopbot software does it correct for my way of thinking and the other two do it wrong. Of course my first experience was with the Shopbot software so that may also explain my thinking. But then also Shopbot calls it "overlap" while the other two call it "stepover". They both pertain to the same operation but use a different name and possibly therein lies the problem.

In the Shopbot software the lower the overlap percentage the less the number of passes. In the other 2 the higher the percent of stepover the less the number of passes. Overlap seems like a clearer terminology to me. In the term overlap I think of the next cut path overlapping the preceding one by the amount specified. When using the term stepover I suppose they mean the actual bit stepover and not the cut path, but I still think of cut path.

Anyway it would be nice if they all use the same terminolagy.

[burchbot]

Like Steve I use V carve pro to plane. I don’t like the 50 % stepover limit. But I think I can trick VCP to stepover more than 50% by telling the software it is using a bit larger than it is. Something to try next time it need it.
Dan