David, did you cut the Walnut bases on the table saw? Looks like a quick and easy project for a CNC.
Fixtures for short production runs
I've mentioned this before but one of the most enjoyable tasks with the CNC is coming up with efficient fixtures for work holding for short production runs.
Today I needed to make a fixture to hold 30 small Walnut bases to cut a slot into for an acrylic plaque. The base is 2 3/8" x 4 3/4" x 1 1/4" high with the front cut on a 25° angle. The acrylic plaque is leaning back at a 15° angle. Since my CNC is a 3 axis with no capacity to tilt the spindle that means I have to slant the work piece if I cut on an angle.
The next part is the fixture can't take me all day to make, has to be designed and built in a short period of time. I have many, many times fallen into the Rube Goldberg time-consuming spiral and designed very complicated fixtures. They work but they take forever to design and implement. Simple is better most of the time. It also helps that all 30 pieces are identical so no surprises when it came to holding the base in the fixture.
So this is what I came up with on today's challenge. The face of the Maple hold down board has a strip of 220 grit paper to ensure nothing moves.
![Wood Table Tool accessory Tool Plywood]()
![Table Wood Furniture Plywood Architecture]()
![Wood]()
![Milling Workbench Tool accessory Wood shaper Tool]()
![Milling Machine tool Tool accessory Machine Tool]()
Including a finishing pass the slot took 33 seconds to cut. It took about 45 seconds to raise the spindle, move it out of the way, vacuum the chips, remove one piece, place the next piece, and then hit 'Go to zero' in Fusion 360 to then start the process over again. And in this case all I had to do was loosen the knobs a little and raise the Maple hold down to remove the Walnut base, then slide another one in its place. Many times I have modified the G-code to raise the spindle and move it out of the way automatically but it's just as easy to do it manually. Now if I had a hundred of these to do then I'd add that code in to do it within the file.
I tried to sand pieces while others were cutting but the cut was over too quickly to do much sanding. So to do 30 of these took about 40 minutes or so. Tomorrow they'll get sanded and shot with one coat of sealer and one coat of gloss lacquer, delivered on Monday which will be a week ahead of schedule.
David
Today I needed to make a fixture to hold 30 small Walnut bases to cut a slot into for an acrylic plaque. The base is 2 3/8" x 4 3/4" x 1 1/4" high with the front cut on a 25° angle. The acrylic plaque is leaning back at a 15° angle. Since my CNC is a 3 axis with no capacity to tilt the spindle that means I have to slant the work piece if I cut on an angle.
The next part is the fixture can't take me all day to make, has to be designed and built in a short period of time. I have many, many times fallen into the Rube Goldberg time-consuming spiral and designed very complicated fixtures. They work but they take forever to design and implement. Simple is better most of the time. It also helps that all 30 pieces are identical so no surprises when it came to holding the base in the fixture.
So this is what I came up with on today's challenge. The face of the Maple hold down board has a strip of 220 grit paper to ensure nothing moves.
Including a finishing pass the slot took 33 seconds to cut. It took about 45 seconds to raise the spindle, move it out of the way, vacuum the chips, remove one piece, place the next piece, and then hit 'Go to zero' in Fusion 360 to then start the process over again. And in this case all I had to do was loosen the knobs a little and raise the Maple hold down to remove the Walnut base, then slide another one in its place. Many times I have modified the G-code to raise the spindle and move it out of the way automatically but it's just as easy to do it manually. Now if I had a hundred of these to do then I'd add that code in to do it within the file.
I tried to sand pieces while others were cutting but the cut was over too quickly to do much sanding. So to do 30 of these took about 40 minutes or so. Tomorrow they'll get sanded and shot with one coat of sealer and one coat of gloss lacquer, delivered on Monday which will be a week ahead of schedule.
David
1 - 11 of 11 Posts
Thanks, guys! Since I posted about the fixture it's only proper that I post a couple photos of the finished pieces. I actually finished these a few days ago but just now taking photos.
![Wood Hardwood Font Lumber Brick]()
![Wood Hardwood Table Wood stain Furniture]()
Those of you with eagle eyes may have noticed the chips in the edges of the acrylic. They had a tube go out in the laser and just sort of barreled their way through getting this cut so I'd have a test piece. The new tube is installed now and the cuts will be clean on the actual pieces going to their customer.
David
Those of you with eagle eyes may have noticed the chips in the edges of the acrylic. They had a tube go out in the laser and just sort of barreled their way through getting this cut so I'd have a test piece. The new tube is installed now and the cuts will be clean on the actual pieces going to their customer.
David
1 - 11 of 11 Posts
