Timing belt driven router - updated pictures

[deanc500]

Hi, Just uploaded a few more photos of the router table we built for
Plastics Plus. Shows an example of how timing belts can be used for X
and Y. In the current configuration, maximum rapid travel speed is
480ipm. Plenty of torque as well.

http://www.axxustech.com/Axxus4x8/axxus_4x8.htm

[HomeCNC]

I posted a picture of this style of movement along time ago. I'm glad to see it in operation.

How does a laser level work to help you keep things flat and true while welding the frame?

[tsalaf]

Dean, interesting design.

What kind of repeatable accuracy are you getting with the belt drive?
Did you source the belt and V groove components in Canada?

Steve
www.tac-pro.com

[deanc500]

Jeff: I made the two sides of the frame first. They are the two pieces that look like bridge trusses. Then I had to insure they were perfectly aligned with each other before welding them together with the three cross members. A rotating laser in the center of the table gave me a reference line to make sure the two trusses were not skewed. I suppose I could have used a regular level, but the laser sure made it easy.

Steve: Resolution is .0005". That was plenty for the plastic pieces that the machine is used for. Linear rails and vee bearing were shipped direct from Bishop Weiscarver. The 10 ft shipping box only weighed 40 pounds, but because of the length, it had to come by truck freight. It cost a small fortune to get it here.

[turmite]

Dean how wide is the belt?

turmite

[deanc500]

25mm

[thielert]

Any stretch?

What kind of load will the belts take? Could you cut 1/4" AL with the machine holding that half thousandth?

What is the gear down ratio from servo to belt pinion?

Tim

[deanc500]

Hi Tim,
The belt is a Gates long length #LL5MR25 Powergrip GT with fiberglass tensile member. The rated allowable working tension (Ta) is 253lbs, but they dont give a spec on ultimate tensile strength. Cant comment on cutting 1/4" AL because we've never tried it. The Belts have been under significant tension for over 3 months now without any sign of stretching or loss of calibration.

The reduction is 9:1 from the motor to the "pinion". The pinion is gates part #P18-5MGT-25 PB. The pitch diameter is 1.128" and it has 18 teeth.

[steveald]

Hi Dean,

Nice design! I have been working on a similar design with the belt above the table rather than below, which allows the "pinion" pulleys to both be mounted on a common shaft running through the gantry.
How did you manage to get 9:1 reduction? It looks like 18 tooth to 54 tooth would work, but I can't find any 54 tooth pulleys.

Thanks,
Steve Aldridge

[deanc500]

Hi Steve, yes I used a common shaft through the gantry as well, but it is connected directly to the motor. Then there is a 9:1 reduction on each side of the gantry from the common shaft to the pinions so the pinions are turning 9 times slower than the motor. The pinions themselves are not involved in the reduction. They only provide the traction for linear motion at a rate of 3.542 inches per revolution.

[Mr.Chips]

Dean,
Good looking machine.
I’m designing a stepper controlled machine about 28” X 36”. I really like your belt drive system, do you think it would work on a stepper driven machine that would be cutting aluminum occasionally?
What would the negative aspects of a belt vs a lead screw machine?
Thanks
Hager

[barbwirebi]

Hi Dean

Great Design
Do you sell any of your plans or "Bill of materials" or info?
I want to use the belt concept and the Vee bearings in my design.

Thanks
Bill