Need Help!- Sheetcam + Scribe + Mach3 - Z Axis Movement

[unixadm]

Hello,

I'm using Sheetcam to generate all of my gcode for Mach3. I have a CandCNC Bladerunner AIO control system on my plasma table, and am using the MP1000-THC - scriber post processor. I have an air scribe attached on a separate pneumatic axis, and all of the offsets and controls work well. So when I call for engraving in my program, it actuates the solenoids and engraves via the correct offset distance. However one issue I have is the Z-axis is still performing moves while the engraving is taking place. That means it's slowing down the engraving by about 2x and also putting more wear and tear on my Z-Axis for no reason. It keeps moving from the .400 safe rapid distance down to .060 cutting distance. Anyone know how to fix this so that when using a tool above 101 (specific for this post processor), the Z-axis movements will not take place until an actual cutting operation?

Any help is appreciated.

[unixadm]

Alright. I took a stab at modifying the post using some information I found in the generic plasma engraver post that ships with Sheetcam. What I did was add in some "if" statements checking if zAxis = true or false. There were a couple of areas for penUp and penDown where I didn't exactly know if I needed to do anything, so I didn't. Anyhow I ran a test program through with the standard MPC1000 - Sciber post and it was full of zAxis movements. I then ran the same job through my modified post and the scribe process had zero zAxis movements. Once I got to a cut routine, the zAxis movements came back. I accomplished this on the toolchange function by specifying zAxis = false for tools over 99 and zAxis = true for anything else.

I ran the table with my scriber air supply off and my plasma cutter off, with a tight grip on my Xbox 360 controller to stop the job if something went haywire. It ran through the engraving function MUCH MUCH faster due to the Zaxis movements being eliminated. Once it got to the cut portion the torch came down, did it's touchoff and retracted to pierce height. Since the plasma didn't fire the program hung up there, but it seems at first pass it is doing what I want. I'm a newbie to this though, so I'm going to include my modified post here and hope someone can validate if I did it right or if I need further edits.

[unixadm]

One issue I've found. If I do a RefZ and forget to raise the torch, I can run into problems with torch drag. Is there a way to insert a G00 Z0.7500 at the start of the program each time, that way the Z-axis doesn't run into clearance issues if I forget to raise the torch?

[unixadm]

Well since this thread is over flowing with information, I just wanted to let those who may find this that Les is working on a updated post for Sheetcam. He sent me a version of it this morning, but it has a few issues.

I manually coded some changes into the original MP1000 - Scriber post that stops Z-Axis movements on Tools 100+, sets a G00 Z0.750 at the start of the program to get the Z-Axis up and to a safe point, and also inserts a G04 P0.15 delay after M09 to allow my scribe axis to retract. I didn't have that problem with the Z moves since that allowed ample time for the axis to retract. Once those moves were eliminated, it was created some light lines on the work when scribing as the X/Y movements would happen too fast. I may need to adjust to delay slightly, but it won't need much.

I'm down without a scribe for a couple of days until my Chicago Pneumatic CP-9361 arrives in place of the knockoff I was using. So I won't be able to test end to end, but my modified post seems to do what I need until Les gets the new one sorted out which is nicer and easier to set up.

[chado183]

unixadm,

I just wanted to let you know that I've been following your posts regularly as I am in the process of info gathering to order a cnc plasma machine. I spoke with Tom (candcnc) and Ron (precision plasma) and think I have a good idea of what I want to buy. Tom had me go to one of your posts on this site and follow your build as what I had described to him was identical to what you were building! I originally thought I wanted to have the rotary cutter on my table, but think I would get more use out of the scriber now that I see what it can do. I have absolutely no metalworking background.....lots of woodworking.....but no metalworking. My wife and I want to start a metal art business on the side at first, then hopefully more. Can you tell me if you would be interested in providing me with what I need for my table to also be equipped with the scriber you have been writing about? I originally was told I would need the 5 axis when I was going to have the rotary, but if I eliminate the rotary and add the scribe, do I still need the dragon cut 5 axis from candcnc? Also, I know I could buy the scriber online, but it is the other items you have manufactured that I would be interested in as well as your purchase list. Any info would be much appreciated!

Thanks and keep us the good work!!!

[unixadm]

Originally Posted by chado183 unixadm, I just wanted to let you know that I've been following your posts regularly as I am in the process of info gathering to order a cnc plasma machine. I spoke with Tom (candcnc) and Ron (precision plasma) and think I have a good idea of what I want to buy. Tom had me go to one of your posts on this site and follow your build as what I had described to him was identical to what you were building! I originally thought I wanted to have the rotary cutter on my table, but think I would get more use out of the scriber now that I see what it can do. I have absolutely no metalworking background.....lots of woodworking.....but no metalworking. My wife and I want to start a metal art business on the side at first, then hopefully more. Can you tell me if you would be interested in providing me with what I need for my table to also be equipped with the scriber you have been writing about? I originally was told I would need the 5 axis when I was going to have the rotary, but if I eliminate the rotary and add the scribe, do I still need the dragon cut 5 axis from candcnc? Also, I know I could buy the scriber online, but it is the other items you have manufactured that I would be interested in as well as your purchase list. Any info would be much appreciated! Thanks and keep us the good work!!!

Well first of all you are in good hands with Ron and Tom. I'm honored to have Tom reference a post of mine to a potential customer - that shows that I'm doing things right, or at least at a level where I'm representing a product I purchased well. Both Precision Plasma and CandCNC have been nothing but a pleasure to work with and both stand behind their products. I am considering bringing to market my own line of plasma tables and accessories, along with other items. If I decide do that, both are my first picks for gantrys and controls. The ideas are still coming to me on the plasma table and accessories though. Having my own plasma table opens up so many opportunities to make professional products that I otherwise could not do by hand. I have a lot of shop equipment, but I would say the plasma is by far the most universal, and even more so if you don't think 2D, but you take 2D parts and make 3D results.

I have a rotary axis from Precision Plasma for my table, however I have not outfitted my Bladerunner AIO with the 5th axis to control it. I have enough projects going on right now that I don't need to get distracted on that just yet. I also don't have a ton of ideas of how I'd use the rotary axis, but I'm sure with time I'll make use of it. One thing I'm looking at adding to my table is an X/Y material holder. This would consist of lower cost linear rails, aluminum flat bar, and a series of small clamps or magnets to act to hold a sheet of material in a fixed location. One issue you have with scribing is keeping the material held steady because you are creating a contact axis with the actual work. In normal cutting unless you mess up your torch height, have a tip up, or excessive dross blow back, your torch should only touch the work when it's doing a touch off. Of course that is not always possible, but its the goal. Holding the material is still important, but not as critical as when scribing. Since I plan to mirror polish aluminum and also scribe stainless, I do not want to waste material or time by having a sheet get moved out of position. For that reason I need to design a rail system which will ride around the perimeter of the water bed. It will still cost me $250-$400 to build this system, but I think it will be cool to simply slide some rails around the work, lock them down, and keep your material well located. This is all food for thought when scribing, but you can also put down plywood, however you can't cut with the plywood in place which limits you to scribing only at that time.

I have spent MANY MANY MANY hours researching and asking questions since starting this project. The concept of my scriber was spawned by seeing some videos of the Dynatorch scriber at first, then I noticed Torchmate had one. I had never examined one up close, but I have used Pneumatics in the past for clamping and such, so it wasn't something totally new to me. Since I wasn't sure how the controls worked, I decided it would be interesting to build my own scribe axis. I considered purchasing from Torchmate, but my PM went unanswered so that just made me put in on the back burner and assemble parts as I figured out what I wanted to do in my head. I feel it came out quite well for my first prototype. It works perfectly, holds accuracy, and the program from Sheetcam also works well with the modified post processor I mention in this thread.

With that said there are a lot of variables when building this axis. I for one will use nothing but roller bearing rails and quality solenoids. It's important to have fine adjustment on your air regulation, proper filtration, and that you don't compromise your Z-axis. I have a three inch stroke cylinder which I feel offers good flexibility between having to keep the axis very low to the work and keeping it high enough to prevent it from snagging on the material. My scriber tip sits about 2.25" above the average material sheet which is a good safe distance. With my slats at less than 2" apart, I have yet to experience a tip up of any kind.

Getting back to your question, you do not need the 5th axis if you are not going with a rotary. You can use M08 to control the coolant / 120V output on the Bladerunner AIO to trigger 120V solenoids. I am already assembling my parts list to build my second prototype which will be smaller, a little faster, but will share a similar footprint as this first prototype. If you have specific questions about parts I have purchased and from where, then please PM me with what you're looking for. I simply have far too many purchases to list.

Regards,
David

[Herb]

Originally Posted by unixadm Hello, I'm using Sheetcam to generate all of my gcode for Mach3. I have a CandCNC Bladerunner AIO control system on my plasma table, and am using the MP1000-THC - scriber post processor. I have an air scribe attached on a separate pneumatic axis, and all of the offsets and controls work well. So when I call for engraving in my program, it actuates the solenoids and engraves via the correct offset distance. However one issue I have is the Z-axis is still performing moves while the engraving is taking place. That means it's slowing down the engraving by about 2x and also putting more wear and tear on my Z-Axis for no reason. It keeps moving from the .400 safe rapid distance down to .060 cutting distance. Anyone know how to fix this so that when using a tool above 101 (specific for this post processor), the Z-axis movements will not take place until an actual cutting operation? Any help is appreciated.

unixadmin..I read this forum every now and then and came across this post. Actually, Sheetcam has a setting to disable the Z movement during scribe. I'll see if I can pull this off by pasting part of post-processor script and color the setting in red and blue. Mine works like a champ.

HTH.....Herb

function OnAbout(event)
ctrl = event:GetTextCtrl()
ctrl:AppendText("plasma MP1000-THC post processor with engraver\n")
ctrl:AppendText("Tools 100 and up are the engraver\n")
ctrl:AppendText("\n")
ctrl:AppendText("Modal G-codes and coordinates\n")
ctrl:AppendText("Comments enclosed with ( and )\n")
ctrl:AppendText("M03/M05 turn the torch on/off\n")
ctrl:AppendText("M08/M09 turn the engraver on/off\n")
ctrl:AppendText("Incremental IJ - set in mach2\n")
ctrl:AppendText("The torch is referenced at cut start and every 500mm of movement thereafter\n")
ctrl:AppendText("Designed for use with Mach3 and CandCNC MP1000-THC and Floating head Touch-n-Go\n")
ctrl:AppendText("Post variables:\n")
ctrl:AppendText("refdistance - set the distance between each reference\n")
ctrl:AppendText("switchoffset - set your net switch offset amount \n")
ctrl:AppendText("\nScriber uses any tool number")
end



-- created 1/1/06
-- Based on plasma1.post


-- Modified 21/6/2010
-- added option for 'nil' plate marker z
-- Added support for plate merker tool type as well as tool number based plate marker



function OnInit()

offX = 0
offY = 0
offZ = 0

post.SetCommentChars ("()", "[]") --make sure ( and ) characters do not appear in system text
post.Text (" (Filename: ", fileName, ")\n")
post.Text (" (Post processor: ", postName, ")\n")
post.Text (" (Date: ", date, ")\n")
if(scale == metric) then
post.Text (" G21 (Units: Metric)\n") --metric mode
else
post.Text (" G20 (Units: Inches)\n") --inch mode
end
post.Text (" G53 G90 G40\n F1\n")
minArcSize = 0.2 --arcs smaller than this are converted to moves

dist = 9999999
refdistance = 10* scale

--Put your switch offset value here
switchoffset =.052
lastz = 0

--Scriber X,Y,Z offsets in MILLIMETRES. Do not use inches here even if you want inch code
--Use the special code 'nil' on the Z axis to disable it.
--In that case no Z values will be output at all while scribing.
--e.g scriberZ = nil
scriberX = 0
scriberY = 0
scriberZ = nil

end

function OnNewLine()
post.Text ("N")
post.Number (lineNumber, "0000")
lineNumber = lineNumber + 10

[Herb]

Oooopps......didn't even look at the year on this thread. Guess I'm a little late with an answer, huh?
Anyway, I tried. Happy cutting and scribing to everyone.

Herb