Steel Gantry Machine 1500x750x200

[Boyan Silyavski]

Hi, good luck with your build!

Can I use L (0,375" = 9,525mm) pitch pulleys with a 12,7mm wide belt from steppermotor to ballscrew? I can get those pulley for free. Together with 240L belt. But this belt is too long and pulley centre hole is 10mm, whish I cant use on Nema 23 anyway. So I have to buy half the pulleys and belts. May as well buy proper with belts and pulleys all around?

No.You can but i wouldn't. The correct belt for this build is 15mm HTD . The correct Nema motor has 8mm shaft. The desired pulley is steel 20t. Belt length maximum 350mm

What ball screw machining are you using when belt pulley will be attached?

Standard. Puley bored to 10mm -/16xx ball screw/

Whole gantry with Z and everything will be close to 80 kg. Can I put my money on 2x Nema 23 3,1Nm together with a decent 70Vdc PSU?

Yes. You are at the limit of it, but given the working area size and my real life experience, you will not need the maximum achievable speeds at all. When we speak of max speeds and similar stuff we refer to heavy industrial application where your machine works full shift trying to produce max result

What HIWIN blocks do most of you prefer: HGH or HGW? Sure it depends from design but I think I will go with HGH20CA from BST Automation.

I buy from him and he has both. They are same price. For the gantry legs the wide blocks. Everywhere else the thin ones.

I would limit Z axis movement with proximity switches to about 100mm + detachable smaller workarea bed when aluminium cutting. This will keep Z in sweet-spot while cutting but also adds weight. I choose unnecessary weight over adjustable bed? But now when I think about it... I will get both actually! Will have to think this over.

No need for this. As you may know i have designed and build this machine. last week i was cutting aluminum fully extended Z, speed 900 mm/min and 1.5mm deep without any problem. 0.8kw spindle only. From the sound of it i could dig at 4mm with the 0.8kw spindle but still my friend does not have cooling which is critical.


Use well the spindle itself for strengthening the Z plate.

However your Z design slightly but critically differs from mine,may be its its weaker, please show better and closer pictures so we could see it in detail/, you could again read when you have time my first build/link in signature/ how exactly i made the Z.

Do you think this long 1610 ballscrew will start whipping on X-axis?

No, don't worry about that. Just design it exactly long. I see you are doing it right. It has been commented many time by more experienced by me members that in real life it will not be a problem. And as i told you before, rarely you will reach similar speeds.


Some comments:

At my second build i was again at the point of making the same mistake as at the first one. Same as what you are doing here. Trying to save on frame bed and machine weight. Now checking prices of T slot track, T slot solid aluminum, T slot aluminum profile, plain aluminum sheet and plastic sheet, i have it quite clear: The bed must be as strong as possible, crossing profiles as near as possible even bed made of welded profiles as the gantry is made, if you will do mainly aluminum.

Why that? Cause all else for serious fixing is darn expensive. Now i am hitting my head these days why i did not weld solid profile 1/2 of the bed for the 2600x1300 i am building for my self now.

So my recommendation here is to make the near to you half of the bed very strong as possible. So later you will not need to pay ridiculous amount of money for aluminum sheets and so.

What i am saying is you weld a strong structure for bed with the chosen profile. Then go to somebody who has shop, like a welder or machine shop. Ask them for their scrap and rests of different profiles. And that cheap stuff you use to weld in between to make it solid. It could be thin walled.