routercnc_MK3

[EddyCurrent]

Nice looking aluminium parts, it will be interesting to see how much improvement there has been, and maybe you could say which new parts made improvements and which parts did not.

[njhussey]

Might finish this thing one day . . .

Looking good, I can sympathise with the above sentiment....I keep trying to carry on with my build but work and other stuff keeps getting in the way...one day!!

[Jonathan]

Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

[EddyCurrent]

Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

http://www.mycncuk.com/threads/7155-...ss+measurement

[routercnc]

Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

Yes, I do plan to measure the stiffness again but it will be at the weekend at the earliest before I can get back in the garage.

Eddy, I've made all the changes together so won't be able to measure individual contributions but my best guess at where any improvements would come from are:

1. Y axis ballscrew plate changed from 18mm plywood to 20mm aluminium (forms part of the 'box' assembly at the top of the Y axis)
> Should improve Y direction stiffness

2. Z axis thin wall aluminium box section and plate arrangement with large offset from gantry changed to 20mm aluminium plate with pockets and lower gantry offset
> Should improve X direction stiffness, plus some Z and some Y due to having much less offset from the gantry

3. Spindle mounting bracket changed from a pair of 20mm thick clamping plates to a converted linear bearing housing
> Probably wasn't a limiting factor in the previous machine, but would in theory improve all 3 directions a bit.

Obviously don't try this at home but whilst I cut out my first part last weekend (from 10mm aluminium) I touched various parts of the machine and felt the vibrations. Not the most scientific method, but found the following, working back from the tool:

Spindle vibration high (not excessive or troubling but high relative to the other points)
Z axis plate vibration high
Z axis rail vibration fairly high
Z axis carraiges (which are on the Y axis) medium /medium low
Y axis assembly medium / low
Gantry low
Gantry sides low

In other words the biggest delta was across the Z axis linear profile bearings, in particular the top one which is the one further from the tool. These are 15mm units. If I was to start again I'd go with 20mm units as they are stiffer, plus they are a bit easier to mount (15mm rails take M3 bolts!), involve less pocketing, plus other general advantages.
But I'm pleased with the progress and if everything is as good as it can be and I've hit the limit of the rail then its not such a bad place to be.

[JoeHarris]

Nice work looking very smart!

[nairepooc]

Hi RouterCNC,

Just spent the day going through your build of the electrical cabinet as you made some good points on my build.
Very interesting build and issues that you worked through along the way, hope mine is half as good as yours ;-)
Are the last posts of the wiring diagrams the most up to date or are there others?
Guess I should move onto your MK4 build guessthere could be some more information in those.
ATB,
Ian

[routercnc]

Hi Ian,

MK4 will run off the same control box so there won't be any updates in that log.

In post #95 in this thread showing the wiring diagram there were some changes made after that:
1. 68V linear supply was actually putting out 72V
2. 30V Switched mode power supply was removed (far right)
3. Z axis driver (MD542) bottom right replaced by another DQM860 driver, and powered by the 72V linear supply
4. 5A fuses going to each X driver replaced by a single 10A fuse shared to both (if fuse blows gantry stops)
5. 6A MCB type D uprated to 10A MCB type D to cope with linear power supply inrush current when switched on
6. 5V power supply cable from PC to BOB was replaced with a dedicated 5V DIN rail PSU (mains driven)
7. A green LED was included in the power on circuit when the main switch was switched on

Very happy with it and works well.

Thanks

[nairepooc]

Many thanks for the reply.
I have been mulling over the design of mine and plan to incorporate many ideas from your build.
Just placed and order with Chalon for a rotary disconnect switch and two type D MCB's 4A & 10A.
On holidays fo rthe next few weeks so taking viso and some cables, plugs and sockets plus soldring iron with me and relax in the sun while building my wiring looms ;-)
Cheers,
Ian

[nairepooc]

Hi Ian,

MK4 will run off the same control box so there won't be any updates in that log.

In post #95 in this thread showing the wiring diagram there were some changes made after that:
1. 68V linear supply was actually putting out 72V
2. 30V Switched mode power supply was removed (far right)
3. Z axis driver (MD542) bottom right replaced by another DQM860 driver, and powered by the 72V linear supply
4. 5A fuses going to each X driver replaced by a single 10A fuse shared to both (if fuse blows gantry stops)
5. 6A MCB type D uprated to 10A MCB type D to cope with linear power supply inrush current when switched on
6. 5V power supply cable from PC to BOB was replaced with a dedicated 5V DIN rail PSU (mains driven)
7. A green LED was included in the power on circuit when the main switch was switched on

Very happy with it and works well.

Thanks

Hi RouterCNC
I now have all my bits around me and startng to work through the wiring schematic;
Parts are;
2 off 36V - 400W PSU (for drivers)
1 off 24V 2.5A mini rail mount PSU
1 off 5V - 2A mini rail mount PSU
1 off CP0-10V BOB (cnc4you)
4 off CW5045 (cnc4you)
1 off UC300 (cnc4you)
2 off E-Stops (2 pos NC)
4 off 24V 10A DPDT rail mount relays
1 off 4A type D MCB rail mount
1 off 10A type D MCB rail mount
1 off Rotary panel disconnect
1 off 10A EMI filter (cnc4you)
1 off Green reset (NO) panel push button
2 off 24V fans (blown air into cabinet)
1 off Green panel mount led (5Vdc - live)
1 off Yellow panel mount led (24Vdc - live)
2 off White panel mount leds (36Vdc - live)

DIN rail mounting and red, black, yellow and fused connectors.

Oh and I have been given a PILZ PNOZ 16S safety unit, just not too sure how to incorporate this.

I did notice that you have an Allen Bradley unit, would this be of use to me or do I have enough above?