Unfortunately I am guilty as charged of opening my mouth very wide in response to a project my friend has won to build a plywood tree 5000mm high and 3500mm at the base widest point. Architect specifications are that it be made of birch ply layers stacked one on top of the other with engineered internal steel structure to support. My friend "plays" in Rhino, and has designed and sculpted a thing of beauty....but now we have to make it!
We have laminated birch ply to be approx 40mm thick, 2420*1220 and the first batch arrives in about an hour and a half!
The equipment we have is Rhino 6 and Aspire 10, the cnc is 3000mm*1500 with 9kw spindle and ATC. We have Amana Tools Ball Nose 12.7mm 46384-K* 5 ( ouch) and they are worth every cent. Also have a 50 mm flycutter with replaceable cutters, and a 19 mm end mill with replaceable cutters, plus other tooling.We have no problems mounting and flipping the material.
The problems include
1 600 or so individual parts to make up the tree trunk, branches, internal support "spines" so we dont want to spend countless hours drawing individual parts and individual toolpaths. So, each sheet is a composite of 3d models which need to be machined both sides to get the desired shapes.
This is the outcome we will get.
- Artist Impression
2. We have been using shit ply 19mm to make some have scale models, and using the 12.7 ballnose to machine.......using a 3d finishing toolpath. All well and good, but it seems to spend a very long time air cutting on the surface. A double sided toolpath takes approx a day !!!!!!, ( and the cnc is no slouch)
We have just over 25 sheets to do.
This is how we go about generating the gcode:
1. Start a new instance of Aspire, set the sizes of material, make sure its double sided machining, z measured from the surface of stock,
2. We import and orientate the model , centre it in the stock and have a value of 8mm overcut distance and create both sides. We end up with a good web between the parts in 19mm stock to be able to hold everything together when flipping.
3. When generating the toolpath, we just use the 12.7 ball nose in 3d finishing mode, to test the sort of outcome we get, which is great, but takes forever.( Selected vectors, boundary offsett of 6.5mm, and offset machining strategy.
Would like to use say the 19mm with a roughing toolpath with zero machining allowance so the 12.7 has less work to do.
If anyone can give some pointers for a combined 3d roughing and finishing toolpath we would be very grateful.
