3D printers/CNC mills

evilvet · Wed Dec 14, 2011 2:18 am

The build is progressing:

The aluminium engineer in Melbourne was a let down but I found a great crew in Sydney who can do exactly what I want for 1/3 Melbourne price. If you are in Oz and looking at this sort of home brew CNC check out Australis Engineering. They are making the whole frame in kit form and shipping it to me ready to assemble, should be here next week.

In the meantime eBay came through with the 3HP water cooled spindle, arrived at the office yesterday.

Pics below, my sparkie is coming over the weekend to test and tag before I power up.

Question:
Anyone have a source for short lengths of VFS motor cable, Belden preferred? All my local wholesalers want me to buy 100 metre rolls.

evilvet · Sat Dec 17, 2011 5:49 am

I have tidings, good news and Christmas cheer.

If JSR, USGF or anyone else is still following, ping now or forever hold you peace.

Post to follow depending on response.

Cheers

jackssmirkingrevenge · Sat Dec 17, 2011 8:03 am

I'm definitely still watching with interest, post away!

Odd, I thought I had posted a comment about the coolness of the water-cooled system.

Heimo · Sat Dec 17, 2011 1:57 pm

I am still watching

evilvet · Sat Dec 17, 2011 3:04 pm

Herewith the first dry assemble of the frame.
This is only rough to ensure the fabricator sent all the right parts.

Looks OK so far, one minor quibble with the alignment holes at one end but overall very happy with what they did. Cost with freight from Sydney was just over $1k. That may sound high but remember this extrusion goes for over $200 per length and I got them to do all the drilling and tapping plus supply fixings.

Anyhow, off to the hardware store this morning to gather bits for making a proper table, then move onto the full assembly.

To do:

Go 20km across town to the only electrical place that sells the cable I need by the metre
Tear down an old photocopier at work, fabulous source of limit switches and optical sensors for free
Ditto an old 19" rack server, free rack mount case for my electronics and VFD
Back to eBay for the linear bearings and rails
Source a 600mm ground ball screw for the Z axis, that's my biggest stumbling block so far.

Photos below

jackssmirkingrevenge · Sat Dec 17, 2011 7:39 pm

Looks like it's going to be pretty sturdy, good stuff!

Heimo · Sun Dec 18, 2011 4:58 pm

looking good so far...

evilvet · Thu Dec 22, 2011 9:57 pm

Too hot to work in the yard, touching 32 outside so a bit of shed time is needed.
Christmas in Oz, 100 degrees in the shade, shed, beer, CNC, browsing SpudFiles.

I made up the linear slide assemblies for the x-axis last night and this morning, pretty happy with them so far.
Everything is still a dry fit mock up for now, I intend to pretty much assemble the whole thing except for electronics to learn from my mistakes then tear it down and do an accurate final build.

After several hours work, my lady's comment was "so it slides, big deal"

More photos

jackssmirkingrevenge · Fri Dec 23, 2011 2:21 am

evilvet wrote:After several hours work, my lady's comment was "so it slides, big deal"

Pffft, if it were up to them we would still be living in mud huts!

Don't let the lady's disparaging remarks put you off, this is looking really nice

evilvet · Wed Dec 28, 2011 5:43 am

Evening all

I am working on the Z-axis design and figure the axis is going to need some compensation for the weight on the ball screw.

The spindle motor and mount come in at 6.4kg, add another 1.5kg for the motor and mounts plus carriage frame etc and I figure I will have 10kg or so suspended on the ball nut.

My figuring says that's close enough to 100 newtons of down force so I am looking at a pair of gas struts mounted either side of the spindle. I don't have a decent drawing of this just now, only a rough sketch but I think I am on the right track.

The question is are gas struts the right way to go given the potential duty cycle of 500 strokes per hour (don't JSR, just leave it alone) or is some type of constant force spring better ? The crude alternative is a counterweight on a pulley but that adds issues with the movement on the Y-axis.

Any ideas ?

ramses · Wed Dec 28, 2011 11:36 am

People use all of those successfully. I will likely use gas struts on my mill to lift its 250 lb head when I convert it.

Since were on spudfiles, I would suggest an air spring consisting of air cylinders hooked up to a large air tank. Pump the whole system to the desired pressure, and it will change very little over the stroke of the air cylinder. Just an alternative.

Gun Freak · Wed Dec 28, 2011 11:43 am

You could probably use a few 3 way valves in there, to appease POLAND

velocity3x · Wed Dec 28, 2011 4:54 pm

jackssmirkingrevenge wrote:Pffft, if it were up to them we would still be living in mud huts!

Indeed!

POLAND_SPUD · Wed Dec 28, 2011 6:59 pm

You could probably use a few 3 way valves in there, to appease POLAND

guess why I like this pick and place machine
http://charliex2.wordpress.com/2011/09/ ... t-edition/

ohh and just out of curiosity
is there any difference between bipolar and unipolar motors? well apart form the fact that they need different drivers

also it seems that there are more IC combining driver + controller in one for bipolar motors than unipolar

evilvet · Wed Dec 28, 2011 7:21 pm

@poland

Ask the expert, Jones on Stepping Motors, an Internet classic
http://www.divms.uiowa.edu/~jones/step/index.html

Bipolar motors are more efficient for a given voltage/current and can be wired in four different ways depending on your current availability. Mine are 8 wire motors wired bipolar paralell.

3D printers/CNC mills

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