Working limits on stinger w/ Mach

[Chris Simon]

Hopefully I can describe this with out sounding stupid so here goes. I have a stinger with Mach3 & VCP and so far i have only done smaller parts and can set the work piece anywhere on the table and set the x, y and z where i want it to be. All the parts to date have been in size range of 12" x 20". The problem or question is how do you set a sheet of ply that is 24 x 36 and set it so the machine will cut that without setting off the limit switches. Is this even possible? I believe the working area of the stinger is 25 x 36. Is there a way to have the machine locate say the center of the working envelope to allow me to set the sheet centered? What I am trying to accomplish is make some boxes out of a sheet of 1/2" ply. I already have the parts drawn in VCP and nested to where they will fit on a sheet sized 24" x 36". If this works i can make 2 boxes out of a 24 x 36 sheet. Or is this something that i need to break down into say 2 separate sheets. Thanks in advance for the help.

[Eric Mims]

you mean you are hitting physical limit switches or soft limits?

[Chris Simon]

Sorry but I have not run the program yet. I am trying to lay this out in my mind before I stand scratching my head staring at the machine and computer. Although I am sure I will hit the physical limits if the board is not properly centered on the machine. I know i can put the center physically anywhere but how do you find the actual (machine) center of x and y. When i run a peice I usually set my home position at the center of the workpiece. I am trying to locate the center or midpoint of both my machine x and y.

[Eric Mims]

I see. I (and assume most others) set their 0,0 usually at the bottom left of the table (near left). But there's nothing wrong with setting your 0,0 at the center of the table/material.

If I were doing it, I would home the machine and manually jog the machine as far left and towards you as possible and take note of the XY coord. Then manually jog it to the far right corner as far as you can go and mark the coord. Then just add the X coord.s (and separately the Y) and divide by 2. etc to get the mid X and Y.

make sure you save the XY position, write it down or save it into Mach3 (not familiar with Mach, sorry), so you can zip the machine there real fast after homing the machine on startup.

[Chris Simon]

Is there a reason why most set up 0,0 to left corner? Well I supose on the larger machines its due to it being closer than the center. I guess its tough to reach the center on a 508. while on the stinger i can reach the center fairly easy. I guess i need to figure out how to home the machine because right now I just manually jog around the router to find the center of the work piece and then set that postion x,y as zero. I have never set a certain positoin as the home position. Do you have some sort of fence/ fixute ect. or just marks on the spoilboard where to set your work piece on the 0,0 where the machine is homed to? For example and "L" shaped bracket or marks to pinpoint the 0,0 that you set.

[Eric Mims]

if I had my druthers, I'd have pop up pins near the corner, or what I might actually do is make some aluminum fence pieces that can slide up past the edge of the spoilboard and then I can either bump my material into the stops or use an L shaped spacer jig to set my material say 2" away from that fence (since on my table the fence would be slightly off the table).. In wincnc you can save home positions.. So you would home the machine using the hard limit switches, use a fence, pop up pins, or simple pencil marks on the table to position your piece, then go to your zero position. By homing the machine using the limit switches, you can come in on any given day, home the machine and then move it to your corner 0,0 that you set and saved the coordinates of, and you're good to go!

[Eric Mims]

I should add, some machines 0,0 in other corners. On my Cobra, the X hard limit switch is near X0 or rather to the far left, and the Y limit is near Y0 or near the control box end of the machine. Since my computer is down on that end and the machine homes itself to that corner, I almost always use a 0,0 somewhere near that corner... but I could set one anywhere I want if I need to.

In my cad program Rhino, I generally draw objects in the positive X and Y, which puts objects in the "upper right" quadrant of the Rhino layout. It corresponds perfectly to how it will come out on the table that way. But again, there's nothing to keep me from centering my designs around Rhino's 0,0 point, or putting them anywhere else for that matter.

[Chris Simon]

Thanks for the info Eric. Now that I look back at my question yesterday I think I got the cart before the horse on my thought process. When I got out to the shop last night I realized what I was asking and what I needed to do was obvious. I was over thinking what I had to do. Thanks again.