Snooker cue case machining ??

[Dale Wills]

Hi,
I have a job that I'm all that sure which is the best approach to take. The customer has requested us to make a snooker cue case out of solid timber. Basically we want a base and a lid with the center pocketed out to house some foam and his snooker cue. We want to have the timber already machined to the correct size and then have the cnc come in and machine out the centre.
We will need to use the G902 position to locate the timber so the centre is machined out accurately. We also want to encase the timber in a frame so as we get better suction and the timber won't move around because it on its own will move without any additional support. How do we offset the G902 on the X and Y axis by 200mm? I think we would also need to select 'no outline cut' so that it only does the internal machining on the part? Do I need the nest to edge of sheet option alwell maybe?
If anyone is interested in giving me some ideas or tips that would be much appreciated.
Dale Wills

[Terry Davis]

Hi Dale, I know exactly what you mean we are doing a job right now that is made out of maple 3x3x44.5 and we had to make a fixture to hold it. As soon as I get it set back up I will post pictures.

[Daniel Vonderheide]

Dale, the SET XSHIFT and SET YSHIFT values will move the origin from the G902 location back towards home a given amount. The issue I see with what you are trying to do is that the nesting software will only write code in the positive direction so you will have to shift the origin to the corner of the piece closest to home. You will need to turn off the outline cuts also. The best way to do this is to nest the piece ,write the code, and then run a test piece made of scrap. Take measurements from this piece and alter the SET XSHIFT and SET YSHIFT values at the beginning of the program to locate the cuts correctly. Making the values larger will move the cuts closer to home while making the values smaller will move the cuts closer to the G902 location. Hope this helps.

[Terry Davis]

Dale, I can't get the pictures of the jig to upload, but its 3/4 laminated on both sides so that that it sucks down well and held in place by other scrap laminated pieces against our homemade flip-op jig that is roughly 72x30 and 6 inches wide so that it contacts all 3 popup pins. The jig is pocketed a 1/4 " deep to hold the maple in place then I screwed aluminum L pieces along the pocket so that I could clamp against the maple parts. I couldn't use any type of fastener into the maple because they need pockets and holes on all four sides. The files were drawn in Autocad as DXF's then transferred to Aspire for tool paths and to write CNC code. I setup a G52L5 offset in the offset table of the Thermwood control to set the machining start position 6" in the X and 12" in the Y away from the home corner on the flip-op jig.

[Rob Davis]

Dale, we never have good, consistent success holding down lumber without a frame/jig. In our case, we take a sheet of melamine or MDF the size of the entire table. Then we cut an exact hole the size of our lumber in this sheet at a location we know. We use this location then to do our machining. We drop the pre-sized lumber into the hole of the exact size and the sheet holds it in place along with the suction. We have also used wedges or shims from time to time to secure it further. It has worked great for us but you obviously cannot tolerate any warp or twist in the lumber, which is more likely in larger pieces. We also drill an oversize hole in one or more corners so we can get a prybar underneath it after to get it out. Probably not ideal, but it works successfully for us as long as your "blanks" are a consistent size. We do use Mastercam on this as well versus eCabs so it makes it a little easier to accomplish.
Hope this is clear and while I am sure there are other probably superior methods, this works for us.