Thread: Tassie Build Steel & Aluminium

Hi Gaza
Being that this is my first build I wanted to make it as strong & ridid as I could the first time.
I have seen a few other machines on here with an RHS gantry and thought that would be best suited to me as the width of my gantry is 1520mm, and I didn't want any distortion while taking heavy cuts.
The reason for putting the beam inside the RHS is so that I could cut out the front of the RHS to allow me to mount the ballscrew back further.
I was going to use channel inside the RHS originally but couldn't get any that the ballscrew mounts would fit into nicely, by using the beam I had the front flanges cut & machined to make the ballscrew sit deep enough to give me about 5mm clearance between the ballnut and Z axis plate. I then had the back machine off to give it a snug fit inside keeping everything straight, I could also then plug weld the back flanges aswell.
It cost about $400 to have the beam machined & have the front faces and ends machined after assembly.

if a picture is equal to a thousand words, here is my abbreviation.
My Y axis ballscrews (20mm double nut) and my linear rails (25mm) turned up today and with the channel I have had cut to length I can start the next stage.

And here I was thinking mine was over the top crazy heavy at about 250kgs all up... Still trying to work out what the final design will look like, but watching with interest.

Hi Headscratcher

I am still adding steel by the Kg.

Tacked up the gantry ends & Y axis channels today, will go into welding shop on Monday and get a fresh bottle of gas and weld up all the pieces. I'm having a short break from work so I will try to get up to the painting stage of these parts by the end of my break.

I am going to the Engineering Expo in Melbourne next week and will try to find limit switches, steppers & drivers while there.

Phil, I would suggest you might pay a lot doing that.

Homann designs and AusCNC (prev AusXmods) are good sources in Australia.

Leadshine digital drivers are excellent are available fairly cheaply on Aliexpress

Phil,
You might want to take a look at OMC Steppers. I bought a stack of smaller stepper motors from them for 3d printers.
They have a wide range, good prices, and delivery was quick - although you do pay for that. No cheap shipping options just DHL, Fedex, TNT etc.
They also sell a range of stepper drivers including Leadshine.

I bought a similar setups from eBay and Aliexpress http://www.aliexpress.com/item/Cheap...658270552.html but probably going to need at least NEMA 34s to move that heavy thing.

Hi all

I have been looking around on the Leadshine website as Pippin88 has mentioned that the digital drives are very good.

I haven't got any idea of the power I will need as yet but thought something like this would be a good choice with the feedback from the encoder as you get the accuracy and low down power of a stepper and a bit higher speed because of the feedback.
http://americanmotiontech.com/produc...0-line-encoder

and driven by this
http://americanmotiontech.com/produc...drive-80vac-8a

or this
http://www.leadshine.com/productdeta...odel=ES-DH2306

Would there be any benefit by using the second controller having built in power supply or would it be better to have everything separate.

Here you go the big brother to my kit. I bought my kit through this mob. Same motors (but bigger) Same controllers (but bigger) same PSUs (but bigger) I am happy with mine. If I was t step up my kit to the next level this would be the way I would go. I am even using their brake out board (at the moment)

http://www.aliexpress.com/store/prod...575412435.html

381oz/in steppers are plenty for my build.

Bigger is not better in steppers. Big steppers have terrible top speeds. For cutting wood you want high speeds.

Yeah but to move and stop all the steel Phil is going to need some serious torque.

Originally Posted by HeadScratcher

Here you go the big brother to my kit. I bought my kit through this mob. Same motors (but bigger) Same controllers (but bigger) same PSUs (but bigger) I am happy with mine. If I was t step up my kit to the next level this would be the way I would go. I am even using their brake out board (at the moment)

http://www.aliexpress.com/store/prod...575412435.html

Those steppers are a terrible choice. Inductance of 22mH - need 150V for optimal performance.
For the 60V that kit supplies, you'd want steppers with inductance of less than 4mH

Phil, Gecko have a good write up on choosing steppers / drivers. http://www.geckodrive.com/support/st...or-basics.html

My gantry weighs fairly similar to Phil's. (200x200x6mm steel tube, plus Z axis). Dual 387oz/in steppers (2.8mH inductance, running on 48V) drive the gantry at 25 metres per minute (20mm pitch screws) for rapids. I haven't pushed it hard with cutting yet, the highest I've gone is 6m/min.

This one seems better at 6.5 http://www.aliexpress.com/store/prod...583920919.html

Hi Pippin88 & Headscratcher

I had no idea about Mh in motors, the link I put up from Leadshine was only an example of the type of motor I was looking at not the size.

Tony, I have printed out the GeckoDrive step motor basics as it is easier to use a highlighter pen on paper rather than my monitor, and I can keep picking it up for reference.

My gantry is still adding weight so I cant do any final calculations yet but a guess is about 110kg at the moment.

I have only got 5mm pitch ballscrews for all axis's on my machine so I might have to use 1:2 or 1:3 step up from my motors to get up to your speed.

Can you tell me what the limit switches you are using as they look like they would be easy to mount on my machine, are they better than mechanical switches in operation and what distance do they operate from.

regards
Philip