Desktop router based on old ISEL components

[LN-JET]

Hello, and merry x-mas!
This is a condensed write up of my first cnc build. It started around mid-summer, when I finally talked my boss out of some 20 year old linear units we had laying in store. They are Isel units of 850mm total length. Three of them complete with steppers and 4mm pitch ball screws. The fourth unit was exactly the same, except for no drive components.





By removing some mechanical stops I found that I could get 600mm+ travel, and still have decent distance between the carriages.
I also dismantled the units totally and cleaned, lubricated and adjusted any backlash. These have seen only a few hours use in laboratory testing, so no sign of wear.



I experimented with several configurations, but decided to use the three powered axis for x and y, and make a shorter z-axis out of the fourth unit.



This is the first and only CAD layout:


A friend that works with automation supplied theese 45mm extrusions:


Gantry uprights were made in a hurry:


First test assembly:


To be continued..

Lars

[CarveOne]

That's looking like it's going to be a nice build. Can you provide any details about the dampers that I see on the motors?

CarveOne

[FandZ]

That's almost like cheating on a diy cnc it looks so easy. How are you planning on mounting the linear slides to the extrusions?

Looking forward to seeing more of your updates.

[LN-JET]

CarveOne; I don't think they are dampers. They are only lightweight serrated knobs.

FandZ; Cheating, yes :-) So much that I decided to pause another build i have. That is a heavy duty desktop mill totally from scratch (no cheating).
Link

Regarding mounting, pictures will follow.

I decided to name the two slaved axis Y and A, and the top axis is X.
I have kept the round Isel motors on the slaved axis. The are about 1.5Nm in torque running bipolar parallell. For X and Z i bought two KL23H286-20-8B from Keling. They are rated at 3Nm.

The making of the Z-axis really involved some hours of diy work..
I wanted 250mm+ to get use of all the heigh under the gantry. I cut down the fourth Isel unit to 180 x 500mm, and reduced the width of the end plates accordingly.



From http://www.maschinen-werkzeuge.com/ I ordered a length of unmachined 16x5 screw, and the special Isel ball nut that fit the carriage. I also got 7200 bearings for the thrust mount.











I have never machined a ball screw before, and I unfortunately don't have a four jaw chuck, so I had to improvise a bit. I mounted an aluminum tube in the 3 jaw, and turned it internally to just fit the ball screw. I also made a close fitting support for the other end. Then by alternately tightening and tapping the jaws with a small mallet, in 15 minutes time I had centered the screw to within 0.005mm. The surface I clocked against was a plastic tube ala the Kurt Bjorn method. The resulting screw works very well.

More to follow.

Lars

[CarveOne]

Ok, thanks. I look at anything related to dampers when I find it. There are commercial ferrofluid dampers that look something like knobs.

CarveOne

[Pplug]

WOW! You are going to be very happy with the accuracy if that machine! I've used and own several techno machines and always marvel at the linear motion components they use. Particularly the way the screws and bearings are covered to keep the dust off of them. You are creating a beautiful machine.

[FandZ]

Originally Posted by LN-JET FandZ; Cheating, yes :-) So much that I decided to pause another build i have. That is a heavy duty desktop mill totally from scratch (no cheating). Link

I gotta say, I don't know which of your builds I like better. That's the first moving column build I've seen. It has left me wondering why I didn't think about that. I'll be following both builds for sure.

[LN-JET]

Thanks for all the kind words guys!

This is how the finished Z looks with the dust covers cut down to size.



I have bought a 2.2kw chinese spindle for the mill project, but I found the 1.5kw version to be almost half the weight, and much neater.
The ER11 collets gives some limits though.



The mount was made so that the spindle can be slid 100mm up and down.
All machining of the larger parts was done on manual lathe and mill at work.
The smaller parts was done on my trusty Emco lathe & milling attachment.



E-chain in the house, and cabling starting to come together.



This is more or less how it looks today:



The electric bit is made up of a midi tower computer enclosure with a Keling 72V 12Amp power supply, and computer psu for 5 and 12 volts, 4ea Gecko 203 drivers, Smoothstepper, Homann designs PD-06 for spindle control,
Huanyang VFD for the spindle. Spindle cooling so far is by a 12V universal fuel pump for carbureted cars. Starts with the spindle through a relay in the VFD.

I have no mounting provisions on the table yet, but have made a few test cuts. Looking good so far:-) It rapids at 9000mm/min (354ipm)
No more pictures to show, as I am away for x-mas holiday. That is why I had the time to write about this build.

Lars

[CarveOne]

That's a very clean, uncluttered looking machine layout. I have no doubt that you will be cutting R/C foamies in no time at all.

CarveOne

[LN-JET]

The enclosed units make for a clean appearance themselves, but of course I tried to get a ok looking machine.
Foamies, well.. I have had a few, but there are many uses for cnc in more advanced modelling. Plugs for fiberglass molds, vacum forming molds, plywood formers, scale details, landing gears, turbine parts, engraving etc.
My interests is not limited to RC either:-)

Forgot to say that total travel ended at 620 x 620 x 280mm

Lars

[LN-JET]

Have spent the last weekend wiring the MPG-2 pendant, and figuring out how to make it work. The Smoothstepper has a lot of inputs, but now I have almost used them all!
Pendant works great, but I think I will have to add a switch to change between jog modes. Step/velocity mode works fine for coarse positioning, but you need to change to step mode for fine positioning. The resolution switch has no effect in step/velocity mode.

Today I brought home a very solid 19" computer rack. It did originally house the electronics that went with the Isel components. The cabinet at the bottom will be used to rebuild the controller. The pc case is really no good.



Lars

[LN-JET]

Two small steps nearer completion.
First I added a two way switch on the pendant. It is set up to switch between velocity and step mode.




Then I drilled the table with 6mm holes at 75mm centers. The machine took care of 2/3 of them. At the back the holes was countersunk with a 10mm face drill.
I had planned to use nut inserts, but I found that ordinary M6 nuts pressed into 10mm holes sits very hard. In addition I put a drop of CA glue on each nut. At last I painted the back side with water based poly.





Lars