Z axis improvement

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THREAD FROM ARCHIVE
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From: David Fisk Date: 12 Jan 1999

I picked up a larger motor for my z axis from ShopBot. The motor, along with the 24 volt power supply I installed, have given so much torque, that I can't make the system bind up even at 1.2 ips! I did manage to make it bind but only with about 190 pounds on top of it. This should put an end to my z-axis problems. The tech support at ShopBot helped me put together a method of sensing depth with a switch. So this should eliminate problems I've encountered with varying thicknesses of wood. Thanks for all the help SHOPBOT!! :-) :-) :-) :-) :-) :-) :-) :-) :-) :-)

[cmrtom@worldnet.att.net]

I am working on a 5 ft Z axis

Has anyone else worked on one

[birdsofplay]

Whatcha really tryin ta do ?

With that kind of "throw" you're gonna run into
lots of tolerance issues that I do not believe
our basic SB frames can cope with.

Could you possibly move the bed up and down
instead of the whole z axis ?

Like the 4 screw set ups used in some of the
portable Planers/drum-sanders which move either the head or, in this case, the bed.

[cmrtom@worldnet.att.net]

We are using the ShopBot to spray paint. Using a large square tube......rack and pinion......and roller skate wheels to let the tube run up and down. Frame is 10 ft wide......10 ft long and 24 feet in length. No Load on the Bot at all and we feel everything will work great. Adding an A and B motor for a true 5 axis machine with using a flip/flop off of the extra circuit....

[ricardo_Cardona@hotmail.com]

Tom,

I’m considering purchasing a ShopBot system to for a custom application. I would like to use the ShopBot to produce 3D foam plugs for the production of large-scale molds for fiberglass experimental aircraft fuselage and wing sections. My specifications will require at least a four-foot Z-axis and a fairly large but lightly loaded carriage. Creating a five-axis system would be a big plus.

I understand from the ShopBot forum that you have been experimenting with a Five foot Z-axis and a Five-axis conversion. I was wondering if you have had any success in this regard.

Please feel free to E-mail me or forward any contact info that you may have.

[danhamm@abc.com]

I had problems with 5mo. old porter cable 3.25
eratic and no power, I had 3.25 Freud on another table so I mounted it on the shopbot, But I
also modified the Z axis to square tubing instead of the pipe, I was getting about 1/16 runout
because of the torque pocketing boxes with larger bits. I like the Freud its quieter and seems to
run at a higher speed. The I tapped the front corners of the sqare tubing for the wheels guides
the back is the same as before seems to work well..

[brian maillet]

would the machine cut a bent piece of laminated
veneer approx two feet radious

the bent piece is three inches wide and one inch
thick

not only is it bent but the flat surface is on diffrent plain or twisted

can the machine trim the edges keeping the edges at right angle to the flat surface

both sides of the three wide piece to be trimed

[bill.young]

Brian,

If I'm picturing this right, you've got a laminated piece that curves and twists at the same time, sort of like the picture below. Two options come to mind; you need to either rotate the part as you cut it or change the angle of the z-axis. Neither way is going to be easy; do you have a lot of these to do?


If you wanted to rotate the part you could make a holding jig that was turned with an indexer, and then synchronize it with the motion of the cutter. The geometry would be pretty tricky.

If you decided to tilt the z-axis you could mount the Z so that it would pivot at it's base and then control the tilt with a ball-screw and a stepper motor. It would be tough to get a simple mount that would allow the z-axis to pivot without being sloppy and causing bit chatter, but I'm sure it's possible.

Bill


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