A set-up technique that served me well today.

This section is for useful tips and tricks for Aspire
Post Reply
User avatar
backyard_cnc
Vectric Craftsman
Posts: 237
Joined: Mon Aug 31, 2009 4:41 am
Model of CNC Machine: SHOPBOT, LIGHTMACHINES MILL, AJAXCNC-KNE
Location: winnipeg, manitoba, Canada

A set-up technique that served me well today.

Post by backyard_cnc »

I find that working on my CNC milling machines I can easily dial in parts to less than a thousandth of an inch in a rather short amount of time but things are entirely different on my old SHOPBOT. The design of this 10 year old PRT SHOPBOT is such as to make some tasks a little tricky (set-up and toolchanges) . Confronted with a revenue job to V Carve a variety of text onto 9 different sized and precut MDF blanks as supplied by the client, I wanted a way to easily find the appropriate area of the blank on which to work. In this case all text was centered Left to right but not necessarily top to bottom. Referring to the photo, I will outline my technique. When creating the toolpaths I set 0,0 to be the center of the vectors to be engraved and created the job size to be the size of the blank. To start I attached a strip of MDF to the end of my table and attached it with 23gauge pins from my most awesome GREX pin nailer. 23gauge pins are tiny but hold great with the bonus of being harmless if you run a bit thru them. With the MDF strip attached I used a 1/4" endmill to cut a reference straight edge (left to right in Y axis) which became my starting X=0 (don't forget to account for diameter of bit when setting the Axis value. Then with a v bit loaded I engraved a shallow V into the strip (highlighted between the tape in pic) which marked Y=0. All the MDF blanks to be engraved were measured and marked for center on the bottom edge which would butt to the reference strip and as each blank was loaded this mark was aligned with the V Carved mark on the reference strip. Once aligned the blank was pinned to the table. This centers the left/right alignment fast and easy. Next I just had to jog the machine to the center of the text to be engraved using a distance determined based on the size of the blank and the text itself. Once positioned I simply run the toolpath using the 2D offset feature in the SHOPBOT software which takes your current position to be 0,0. In other software the workplace coordinates systems accomplish similar.

This worked out very well and all 9 blanks were mounted, referenced and cut in a fairly short period of time and all alignments look good. If this doesn't make sense or you have a question please feel free to ask. I found this technique worked flawlessly for me and I suspect I will use it again. Sorry the picture is less than perfect but shop dust killed my real camera and my smartphone camera is sensitive to my shakey hand and this gives the fuzzy pics which look ok on the small phone display but are less than perfect on a hi-res computer display.

Gerald
Attachments
IMG-20130704-00128.jpg

Lameiii
Vectric Craftsman
Posts: 189
Joined: Thu Dec 16, 2010 5:50 pm
Model of CNC Machine: Romaxx WD1
Location: Dupo, IL

Re: A set-up technique that served me well today.

Post by Lameiii »

I''m curious about the pegboard. Do you use this to mount projects for carving?
If so could you give me some detail on how you do it.

Jim

User avatar
backyard_cnc
Vectric Craftsman
Posts: 237
Joined: Mon Aug 31, 2009 4:41 am
Model of CNC Machine: SHOPBOT, LIGHTMACHINES MILL, AJAXCNC-KNE
Location: winnipeg, manitoba, Canada

Re: A set-up technique that served me well today.

Post by backyard_cnc »

I have a grid of 1/4"-20 tapped holes on the main table top and the pegboard is sacrificial rather than the MDF table top itself. The holes in the peg board can align with the table grid holes, if need be, to allow clamping but generally I just use the 23gauge airnailer to firmly attach material. I try to preserve my tabletop as best I can because it is a PITA to replace it or even to flatten it for that matter. Smaller sacrificial pieces are more desireable and pegboard is cheap so it works out well al around.

gerald

rbraeking
Posts: 35
Joined: Mon May 13, 2013 10:03 am
Model of CNC Machine: sscncrouter.com Mdl FS1325A
Location: Santa Fe, Texas, USA

Re: A set-up technique that served me well today.

Post by rbraeking »

I use a similar technique if I understand it. My machine zeros at the corner based on a 96 x 48 sheet of material. I reference my y and x then move to zero. I measure from my machine edges to the mark on the workpiece. Then advance to these positions and zero both the x and y. While that job is cutting I can be mounting and measuring the next one if there is room on the table. My spoilboard is drilled with 1/4" holes on 2" centers. I mount material using shelf pins for stops and 5° opposing wedges for clamps. If there is a risk of hitting the shelf pins I put a 3/4 x 1 sacrificial strip between the shelf pins and workpiece.

Post Reply