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Designing a Large Slab Planer/Flattener1/13
So I am in the beginning stages of trying to design a tool to ease the process of flattening large live edge wood slabs (up to 4'x8') There is a well known article in FWW about making a sled for a router and some rails for it to ride upon. I'd like to take that idea to the next level by using a huge face mill (6-10"?) and an industrial motor with variable speed control. Basically a super Router. I plan to build the sled out of steel and the rails out of steel or aluminum tubing and have bearings of some sort for smooth operation and movement in the X-Y axis....think CNC machine without the computer or automated controls; I would move the carriage manually, possibly with a hand crank and chain drive system.
Note: Lucas Sawmills has an attachment that does this same type of thing for their system, but that only works if I already have their sawmill, which I do not. I have a woodmizer.
The goal here is to have a stronger machine than a basic router that can cut more wood in one pass. It serves as a jointer/planer combo for slabs that are too big for my machinery. A shroud or hood for dust collection would be essential as well.
The part that I need to get advice on is the Motor-Mill combination. I figured on finding the biggest face mill that seems reasonable, with replaceable cutter inserts, and then have an arbor/collet type of adapter machined that would attach directly to the output shaft of the motor (Baldor Industrial). I could use a variable speed control for different woods. Issues that I see are determining the proper cutting rpm for such a large mill, reducing chatter and vibration, the interface between the motor and the cutter and sizing the motor appropriately.....I obviously want as clean of a finish as possible, similar to what I would get if i put this slab through a gi-nourmous planer, which I cannot afford.
Anyone with any ideas please let me know!
By the time you invest your time, money and resources into this thing you could buy a used CNC and be done with it. I have a 4x10 CNC and flatten slabs using a 100mm cutter. takes longer to put the slab on the table than does it to surface.
I have been using a CNC to flatten live edge slabs since '99. I use a spoil board flattener with insert tooling - it gets 'er done.
I wrote software to automate the process - including parameters for length and width along with the step down value per pass.
It's the only way to fly.
Bruce and CNC, how much do you take off in a single pass with the spoilboard cutter? At what feed speed?
Joe, I am using a 100mm insert cutter, Leitz. My feed rate is set to 6 meters per minute but I can slow that if needed using a dial on the CNC. Most of the slabs I get are NOT flat so the first several passes won't contact the whole slab. To start I use 10mm cutting depth but once I get to full surface it might be 5mm. I have a 4x10 pod/rail machine that will handle 7" thick, sometimes hot melt a 12" square piece of melamine under the slab at each end so that the vacuum cups have something to suck against. When I have a flat surface I'll turn it over and pry off the melamine and surface the other side.
I have to give credit to Brian Personette for helping me with the programming. Using a single tool path as a sub program, based on the part size it makes as many passes as required to surface the part. I only have to enter the part size. To achieve successive passes I stack the program and change the thickness on each stack.
I set the tool to cut zero depth and change the cut depth by changing the part thickness. In that way I can have a different depth of cut on each stacked program by making the material thickness different. My pods don't release until that last program in the stack is run.
I must say it makes a awful mess removing that much material, clean up is a pain. For my effort I charge a hundred and fifty dollars and up.
There's a company in Australia that has designed and built what you're describing. See youtube demo link below.
Only one unit so far in the U.S., and it's installed at Newport Nautical Timbers in Bristol, RI. I've had them use it to flatten several slabs for me. The nice thing is that the router travels longitudinally, not crossways (like on a router sled) so you don't get blowout on the sides/edges.
They cost about $18k through a distributor in Canada.