Hi to you all and Stepper Motor size Question

[Roy Oxley 2Participant @royoxley2]

I am new to forums in general, I am now retired and as a committed tooloholic I am at last being able to play with my toys. I am at present looking to build a cnc router, using the moving gantry principle. I am experiencing problems in finding out how to calculate the size of stepper motor that I will need to drive the gantry. I will be using ball screws and ball slides so that there will be minimum resistance. The weight of the gantry will be about 4kg. I look forward to any assistance available.

[Roy Oxley 2Participant @royoxley2]

[John Stevenson 1Participant @johnstevenson1]

Without more information, hard to say but loads have been built using a type 23 stepper around the 3Nm rating driving the ball screw 1:1 thru a suitable coupling

[Roy Oxley 2Participant @royoxley2]

Hi John I have looked a many cnc kits and my gut feeling is that a type 23 should do it, but being a Yorkshireman I want to know how to calculate it before I spend any hard earned cash.

[Neil WyattModerator @neilwyatt]

Hello Roy,

Welcome to the forum.

Neil

[John Stevenson 1Participant @johnstevenson1]

Posted by Roy Oxley 2 on 01/04/2016 17:18:14:

but being a Yorkshireman I want to know how to calculate it before I spend any hard earned cash.

.

It's the square root of how many butterflies exit your wallet

[duncan webster 1Participant @duncanwebster1]

As a fellow tyke I can assure you that butterflies can't live in our wallets as they don't get to see daylight often enough.

[Iain DownsParticipant @iaindowns78295]

Hoorah for God's Own!

Iain

[BazyleParticipant @bazyle]

By router I assume a woodworking machine rather than a CNC mill. This one if you search has a blog, a long one, by someone who made it and improved it over a year or more. There is someone in the Bristol ME club who displayed one about 4 years ago at their show and might be able t give you some measurements of friction etc.

If you really want to calculate it you need to look at the ball screw specifications for the torque required to overcome internal friction, likewise the slides. then examine the energy needed to pull the cutter blade, on each revolution, into the material as it will be trying to push itself back off the job rather than cut into it. Some of this energy comes from the rotational inertia of your intended spindle, which you can measure. And so on. I could give you full details for a suitable fee – my father was from Bradford and my grandfather from Aberdeen.

Baz – south of Watford

[Roy Oxley 2Participant @royoxley2]

I have found a great article that gives me what I want plus spreadsheet at

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjEo7vCoO7LAhWDph4KHZdqAyoQFggcMAA&url=http%3A%2F%2Fwww.mycncuk.com%2Fthreads%2F1524-What-size-stepper-motor-do-I-need&usg=AFQjCNFFOLI4Cte7ayvrp8ZrYlhu_Q5OQw&bvm=bv.118443451,d.ZWU

Edited By JasonB on 02/04/2016 07:33:01

[Michael GilliganParticipant @michaelgilligan61133]

Well done, Roy

… The answer is probably something in a NEMA 23 frame

MichaelG.

.

P.S. … for the convenience of others, here is Roy's **LINK**

Edited By JasonB on 02/04/2016 07:33:26

[ManofkentParticipant @manofkent]

A friend of mine has been puzzling over this issue for some time. The power ratings of Stepper motors seems quite a dark art!

So the link will be a great help. Thank you.

John

Edited By JasonB on 02/04/2016 07:33:54

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