Suggestions wanted.

[manolo74]

Hello everybody, I'm new here and have been doing alot of reading. I am in the process of building a 4' x 8' operating table out of steel.

I'm still a little fuzzy on the electronic components needed, I want to put together a 4 or 5 axis machine. I have found the step motors which are Nema 34 874oz.in which I think would be sufficient for this machine. If somebody can please let me know what other electronic components would I require.

[dertsap]

i would suggest gecko stepper drivers above any ,

[manolo74]

Originally Posted by dertsap i would suggest gecko stepper drivers above any ,

I need a driver for each motor? Which gecko model would be ideal?
The motors I found are they any good?
Can somebody please tell me what is needed:

-Step motors
-step drivers

what else?

[ger21]

What are the voltage and current ratings on the motors? You'll also need a power supply, and you'll probably want a breakout board. And a PC running some machine control software.

[manolo74]

Originally Posted by ger21 What are the voltage and current ratings on the motors? You'll also need a power supply, and you'll probably want a breakout board. And a PC running some machine control software.

6.6v and 3.0amp



Motor Frame size: NEMA 34
Holding Torque: 63 kg.cm / 874 oz.in General Specifications:
Step Angle: 1.8 Deg ± 5°
Insulation Resistant: 500VDC 100M Min.
Insulation Strength: 50Hz 1Minute 500V Min.
Ambient Temperature: -20 ~ 50°
Operating Temperature: 110°C Max.
Radial Play: 0.02mm Max.
End Play: 0.1-0.3mm

85BYGH450C-03

.

I will also need a breakout board like you have said and yes a power source.

[manolo74]

For the ACME rods are there any suggestions as to thickness and pitch?

[yukonho]

Hi Manolo.
Where in Canada are you?
I would strongly suggest reading through these forums a bit more. There is a lot to learn, and you are starting with a very large machine here, educate yourself or you may have an expensive mistake on your hands.
If you are using leadscrews, you will have a huge whip issue over the 8 foot, even the 4 foot span. You will want to use a leadscrew with a very high pitch, like a 1/2-10 5 start which is effectively 2 TPI. Check out dumpsterCNC for leadnuts for this.
Colin

[manolo74]

Originally Posted by yukonho Hi Manolo. Where in Canada are you? I would strongly suggest reading through these forums a bit more. There is a lot to learn, and you are starting with a very large machine here, educate yourself or you may have an expensive mistake on your hands. If you are using leadscrews, you will have a huge whip issue over the 8 foot, even the 4 foot span. You will want to use a leadscrew with a very high pitch, like a 1/2-10 5 start which is effectively 2 TPI. Check out dumpsterCNC for leadnuts for this. Colin

Hi Colin,
I'm in Montreal, and you? It is a large machine, I've been reading through most and lot's of stuff to take in. That is one of the reasons for asking for suggestions, reading through I have seen there is alot of good people here willing to help. What do you think of the motors?
Thanks for the info and congradulations on your baby, boy or girl?

[jcc3inc]

Sir,

I would seriously use rack and pinion for drives. They are relatively easy to implement, trouble free, backlash free (spring loading of pinion into rack), and
economical. Consider 20 degree pressure angle, 20DP rack from Standard Steel Specialties, 803-486-9500. My recollection is that the price is $23.20 for a 6 foot length. Pinions can be had from Martin gear; use at least 18 teeth pinions for no undercutting.

Regards,
Jack C.

[Goose80]

how about 425ozin Nema 23 sold by Xylo?

Are they strong inuff for 1200x2400mm machine?

[Greolt]

Manolo have you looked at the Mechmate? It is about the size that you want to build.

Gerald, the designer of the Mechmate, is providing detailed plans and lots of assistance for free.

Even if this is not exactly what you want it would be well worth spending some time reading and
looking at his site. A lot of the issues you face with a machine that size have been well thought out.

http://www.mechmate.com/index.html

[yukonho]

Goose, depending on the weight of your gantry and router, the 425's should work fine. The biggest question will be, how fast can I go with them. I will be running 480 oz-in motors on my 3 foot square machine, but at a much higher voltage and current than the xylotex will go. I plan on using 1/2 - 10 5 start, or 2TPI screws. Using a higher pitch screw will keep your motor spinning slower, keeping torque at a maximum.
Manolo.
I moved from Montreal two years ago.
Multiply your motors voltage by 20 to get the PS voltage, rated voltage for good performance. This means 132 volts !!! to run these motors well. I hope that this is right and I got my factors correct, anyone please chime in if I am wrong. I run 68 volts on my gecko drives and 3 volt motors. Check out homeshop cnc for steppers, I am happy with the ones I got from there.
Colin