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thorphar
02-08-2014, 02:18 AM
I am making a 1.6m by 1.2m cnc machine i have found a website in the uk called http://www.zappautomation.co.uk/ I have managed to find that the SY60STH86-3008B Nema 23 Stepper motor (http://www.zappautomation.co.uk/sy60sth86-3008b-nema-23-stepper-motor.html)

would be the best stepper motor for all of the axises. I have a few problems though, i cant use just one stepper for the y axis as the machine is being built for custom sizing meaning there cant be a cross bar for the leadscrew. I think the only other option is to use two stepper motors in conjunction as if i just use one i will get lag on the other side. Does anyone not agree with this? If not I assume i need to get 4 drivers. I have found that the Leadshine DM856 CNC Driver Digital Hybrid Stepper Drive 80VDC/5.6A driver would be the best one for the job as it would allow me to run the stepper motors very fast. I need to find a power supply to power all the drivers and steppers. Please could someone help me.

EddyCurrent
02-08-2014, 09:57 PM
This is also a popular site; http://cnc4you.co.uk/
Yes you will need 4 drivers if you use 4 motors.
It's best to make your own power supply, some info here; http://www.mycncuk.com/threads/6624-Power-Supply-Build-for-Router-CNC?p=49938#post49938
but there's loads more if you search this forum, you need to ensure the voltage is about 70v minimum to get the best from that setup.
You want a 'linear supply' not a 'regulated supply' because the linear ones can absorb excess back emf from the motors during fast stopping for example.
Toroidal transformers are got here; http://www.airlinktransformers.com/chassis_mounting_toroidal_transformers/chassis_mounting_toroidal_transformers_standard_ra nge/
I got my capacitors here; http://www.rapidonline.com/FFSearchResults.aspx?query=bolt%20capacitor&filterSearchScope=1
they also have the bridge rectifiers.

deisel
02-08-2014, 10:17 PM
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JAZZCNC
03-08-2014, 12:45 PM
I have found that the [FONT=arial]Leadshine DM856 CNC Driver Digital Hybrid Stepper Drive 80VDC/5.6A driver would be the best one for the job as it would allow me to run the stepper motors very fast.

When you say "very fast" what speed are thinking you'll get.? . . . . . Steppers in general don't spin very fast or should say are not much use spinning very fast. Much above 800-1000rpm and they lose fair amount of torque which drops off to nothing very quickly above 1200-1500rpm and at 1500-2000rpm there's next to nothing left.
Speed you get from steppers is mostly down to voltage so is proportional to the voltage provided to the drives and why Eddy current suggested 70vdc but there are limits and for these motors 70Vdc is close to the Max not the minimum. Running at 70vdc is considered working above the design threshold but in practice they handle this no problem and are reliable but going higher can produce excess motor heating which will shorten there life.

Also Be aware that Steppers produce Back EMF so are effectively dynamos when deaccelerating so you need a safety margin between voltage supplied to the drives/motors and the drives maximum voltage rating. Now how large a margin is slightly affected by the type of supply you use and it's for this reason why Unregulated Toroidal supplies are best because they absorb back EMF better thru there capacitors. So if using Toroidal setup you can effectively run closer to the drives Max voltage limit
Now That said even with Toroidal PSU the Maximum voltage I'd run is 75V on 80Vdc drives and for best balance of speed/motor heating and drive/motor life expectancy then I would run that at 70Vdc which is what I consider there MAX sensible working voltage. They will run higher but you'll kill them quicker.

Regards the drives then the DM856 are good drives but because your going to slave 2 motors to one axis then I recommend you go for the better EM806 or AM882 as they have stall detect and fault output which you can use to E-stop the machine if one motors stalls and the other doesn't which if your wanting high motor speeds there is a high probabilty will happen.!
I'll just point out that if your wanting high traverse speeds Ie Rapid speeds or cutting speeds then the correct way to achieve this is by selecting the correct linear setup Ie: screw pitch etc not soley using motor speed. Motors give a certain amount of torque on a RPM curve so matcing the screw pitch to give the speeds required at certain RPM/Torque is the way to do it not just find fast spinning motors.

thorphar
03-08-2014, 03:24 PM
Thank you for the information. I am going to use 16x4 or 20x4 leadscrews so I should be able to get the speeds i want. I have found the AM882 drivers here (http://www.aliexpress.com/item/New-Leadshine-AM882-Stepper-Drive-Stepping-Motor-Driver-80V-8-2A-with-Sensorless-Detection-SM414-SD/570168083.html) Would you agree with getting these ones. I will aim to make a 70vdc linear power supply with soft start. As i mentioned above and am looking to use leadscrews for all the drive mechs, however i need to find some nuts. Does anyone know of a cheap source of leadscrew (Trap) nuts? Thank you so far

JAZZCNC
03-08-2014, 05:01 PM
Thank you for the information. I am going to use 16x4 or 20x4 leadscrews so I should be able to get the speeds i want.

Why lead screw.? What speeds do you require and what you cutting.?

Those AM882 are fine but just be aware you'll have VAT to pay and customs/shipping handling charge so they won't work out much cheaper than buying from UK and you'll have piece of mind can return to UK supplier. I find drives and BOB's are the one thing worth buying in UK even thou made in China as they are what give the most hassle or easily damaged by wiring wrong.

Boyan Silyavski
03-08-2014, 11:44 PM
Most people here on the forum agree it seems that 1610 is perfect for all axis and 1605 for the Z. Forget about lead screws. yes, thats the motor that goes super well with AM882. I bought all from Zapp. Yes, you need 4 drives. The toroidal transformer i bought from ebay from Germany and from china the rectifier and the capacitors, is called by chinese a regulator.

EddyCurrent
03-08-2014, 11:51 PM
Please could someone help me.[/FONT]

That's why this forum exists, there is help all the way.

thorphar
04-08-2014, 12:34 PM
I have found the em806 driver on zapp but cant find the am882 does this really effect the end result. Sorry for my idiocy 1610 and 1605 aren't those leadscrews, so why say forget? If they are and you suggest using these do you have a good supplier for leadscrews and nuts, in the uk or really cheap from anywhere else, it just seems that zapp nuts are far too expensive, i was thinking of making them myself ?
Oh here is a picture of the router so far (https://drive.google.com/file/d/0B6vERS9G-YoldGtoSzZGYjZxNG8/edit?usp=sharing).

deisel
04-08-2014, 01:17 PM
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Boyan Silyavski
04-08-2014, 01:48 PM
I have found the em806 driver on zapp but cant find the am882 does this really effect the end result. Sorry for my idiocy 1610 and 1605 aren't those leadscrews, so why say forget? If they are and you suggest using these do you have a good supplier for leadscrews and nuts, in the uk or really cheap from anywhere else, it just seems that zapp nuts are far too expensive, i was thinking of making them myself ?
Oh here is a picture of the router so far (https://drive.google.com/file/d/0B6vERS9G-YoldGtoSzZGYjZxNG8/edit?usp=sharing).


:toot: Wait a minute :toot:

No offence but your design will fly to pieces on the first error when something hits something. By the look of it you can expect speeds in the range of 10 IPM with depth of cut no more than 1mm.


Lets start from the beginning.

So lets start from scratch with the help.

What is your budget? What you expect to do exactly with the machine?

thorphar
04-08-2014, 02:02 PM
I should explain that this is a project for my A2 at college. I except somethings not to work too well as this is just a prototype . I wanted to cut at least mdf, plastic and some 3d foam routing. The concept is based on an exciting machine that appears to work ok. The post here really is to find the correct electronics so that they are transferable to my final machine. The idea is to make a basic machine and then use it to cut the panels out for the end product that would be stronger and be able to withstand harsher loads. Also the photo does not show the whole structure behind the bridge, which is quite strong. My budget for electronics and drive mechs is around 600-700.

Boyan Silyavski
04-08-2014, 04:03 PM
I should explain that this is a project for my A2 at college. I except somethings not to work too well as this is just a prototype . I wanted to cut at least mdf, plastic and some 3d foam routing. The concept is based on an exciting machine that appears to work ok. The post here really is to find the correct electronics so that they are transferable to my final machine. The idea is to make a basic machine and then use it to cut the panels out for the end product that would be stronger and be able to withstand harsher loads. Also the photo does not show the whole structure behind the bridge, which is quite strong. My budget for electronics and drive mechs is around 600-700.

OK, , i thought it was something like that.

Nevertheless you can reinforce the gantry sides, just do a search for MDF cnc and you can get better idea how to reinforce things with minimum cost. And dont forget to paint it.


Now ball screw is one thing and lead screw is another thing, not the same as you call them. You want ball screw, given the current prices of chinese ball screws..

Having in mind your budget, the buy from China directly. the savings will be considerable. AM882 is protected against all - improper polarity of the power supply, so just be carefull and there will be no problem. Will pass you with PM from where i buy stuff. Not that there is a secret - BST automation, many buy from him. This would be cheaper than LMB and any other,+ he is a very reliable seller. He has all you need or will source it very fast.

Hope that helps.