To be honest, I have had something similar happen - but I don't know what it really the answer.

1st question - does mach show any indication that it has stopped? Or is constantly running the code queue?
2nd question - does the drive or drives disable? Or go into thermal protect?
3rd question - do you have proximity limits on your z axis? ( I have had to isolate the 12mm body from the machine metal mounting because the ground issue has caused my machine to either stop, or caused the z axis to "tick up and down" without direction from Mach IF spindle was running.
4th question - does your spindle have ceramic or steel bearings? And can it ground itself thru the tool bit?

It sounds like an EMF / Grounding issue. Have you tried grounding the alum part your cutting?

Nice work Marko. A question, What´s tool do you use to draw these project?

Thanks Sean,

1. Mach keeps on rolling with code like nothing has stopped.
2. Motors are cool and even below 37 C
3. I dont have proximity sensors yet.
4. Dont know about bearings, but i think its not ceramic.

I have felt some static charge when I was touching the control box, but I ignored that and that never happened again.
Can it be that my spindle is doing some static and stoppping the motors?
Or is it that my drivers and control board have connection with metal?

Thanks Leonardno,

I mostly use artcam, solidworks and aspire 4.

I had an intermittent fault with the machine stopping.

Check your parallel port connections.

Also take the cover off the computer and vacuum inside especially the printer output.

I also put in a new earth on the computer and machine.
It has worked very well since.

Hope it works for you.

Thanks Al,

Was just doing some wood cutting, and msachine stopped again.
Well that was revealing, and also anoying, so i tried to move it, and after pressing, it came finaly back to life, withoot me touching anything else.
So I set it to move, and kick it with my leg the control box, and it stopped again.
That is good thing, coz i know now that my cable if messed up, or something in control box.
Will deal with it tommorow.
Keep you posted.
Some aluminium cuts pics:
http://i1258.photobucket.com/albums/...ps1845c9f8.jpg
http://i1258.photobucket.com/albums/...ps3c8bd63b.jpg
http://i1258.photobucket.com/albums/...ps5ecbd90d.jpg
http://i1258.photobucket.com/albums/...ps881448b5.jpg
http://i1258.photobucket.com/albums/...ps1bdf08cf.jpg

Hello again. Im back with some news.
I discovered where was my problem.
I found my 5 V cable to my control board to be untrustworthy. So I tested it, and when i started to move it, the machine stopped.
Correct me if I am wrong, but if i physically stop my stepp motors, will the mach keep rolling the code? It happened 2 or 3 times when machine stuck in the melted aluminium, and lose almost no step, but was moving for few seconds.
Anyway. I redone the wiring, and machine worked in 2 times for 4 hours straight.
This where my new problem started.
I was cutting some reindeers from plywood and I set my artcam cut speed 100 mm/s.
As I loaded in mach, the machine did not go as fast as that. It moved only on straight lines with that speed. As mostly are curves, the job what was ment to do in 45 (artcam approximation) mins, stretched in 4 long hours.
Can you help me with that.
Not sure is the Mach 3 or artcam problem.
some pictures:
http://i1258.photobucket.com/albums/...ps320722b0.jpg
http://i1258.photobucket.com/albums/...psb8aee42d.jpg
http://i1258.photobucket.com/albums/...ps4f220fcd.jpg

Marko.

100mm/s is 6000mm/min F6000.

Check your nc program and see what the feed value is, it should read F6000.

When the machine is cutting look at the Mach screen feed value.
It will show the commanded feed and the actual feed.

Yes the programm will still run if the motors are jammed or removed.

Nice deer and workshop stove.

HI Al,

Machine says its F6000 but it moves around 5 mm per sec at some areas, mostly around 20 mm/sec and only on straight lines it get to full speed at 100 mm per sec.
Thanks for the info about the program and parallel cable.
Was thinking is it CV problem, or the computer muscle problem, but now I cant tell.
The job should be done in 45 mins flat, and it took almost 4 hours.

Stove is a work of art, the only thing keeping it together is the sheet metal around the edges, coz the inner plating fell off.

Marko,
Yes, the machine will slow down when cornering or changing directions drastically.

Now its obvious that its software setting or tuning error with your units. It can be anywhere, might be u forgot to put in the drive ratio in Mach3 set up, even be in your G-code... Give it a round of check & you might just find it hidden in plain sight.

Hi marco….

Sorry to read your trouble…and dble sorry, I’m not confident enough to assist you !!
BUT…may I ask where did you get this nice dear drawing ?
I’d like to produce some for this time of the yr !
Beat of luck with your….troubleshooting !
Robert ;)

Hi Ken,

Not sure what you think about drive ratio? If you mean about reduction, and something mechanical, then my circles should differ from what I want.
The machine is calibrated and dimensions are in tolerances.
I have my susspison on artcam 2008, but how then the artcam itself says it takes 45 mins, 4 time shorted then then what really need.
Will test it tomorrow, i had no time to waste and the job needed to be done.
Not sure about my computer also, its a bit on slow.

@ Robert
I found it online as a free dfx.
Feel free to download it

Tks for sharing ;)

If you work out the perimeter distance of the part or parts that you are cutting and divide that by feedrate, that will give you the cutting time in minutes.

For example. 5000mm distance. 2500mm/min feed, 1 pass.

5000/2500 x 1 = 2. 2 minutes.

As for what your CAM softwear says, take that with a pinch of salt.

Thanks Al,

From that point on, I was comparing the CAM and real time, and its always different.
Sometimes shorter, sometimes longer.
In the meanwhile, here are some pictures.
http://i1258.photobucket.com/albums/...ps894e0880.jpg
http://i1258.photobucket.com/albums/...ps82ebd645.jpg
http://i1258.photobucket.com/albums/...pse406d95b.jpg
And creating a table for cnc, I call it chuck bolt table.
Got finished today with other plate. All the screw paths (or what its called) I did manually, all 96 times. Still planning to get a back plate with channels for coolant liquid.
http://i1258.photobucket.com/albums/...psc5e053e8.jpg
http://i1258.photobucket.com/albums/...ps3f327768.jpg
http://i1258.photobucket.com/albums/...psc4c036c8.jpg
http://i1258.photobucket.com/albums/...ps8c653952.jpg
http://i1258.photobucket.com/albums/...ps5fd9dafa.jpg
http://i1258.photobucket.com/albums/...ps7217a176.jpg
http://i1258.photobucket.com/albums/...ps5cdd25d3.jpg

Great pics. Well at least the first 3.;)

Were those pics focused on the reindeer or Santa's Helpers? Ha Ha.;) I bet you hands are a bit sore from tapping.

Is the plate going to be use to mount materials you mill? Just curious, how is it going to be mounted itself, and onto what machine?

I went there to take pictures of reindeers, but santa helpers looked much better.
Hands are killing me, and I have bladders of water all over my palms.
I have 2 plates finished, and it will be used to mount materials.
I play to put those plates on an aluminium plate, and fix it to the table of my MM.
Trying to get vibrations out, and some coolant pump and liquid into the fixture.
Also, I have to level it down.
Any sugestion about that coolant table?

Long time no see.

Some recent photos.
Im switching to linear bearings coz the solution ov V groove rollers is bad.
http://i1258.photobucket.com/albums/...ps82349ed2.jpg
http://i1258.photobucket.com/albums/...psb27288c5.jpg
http://i1258.photobucket.com/albums/...psfdc0b27c.jpg
http://i1258.photobucket.com/albums/...pscac56f13.jpg
http://i1258.photobucket.com/albums/...ps5139600a.jpg
http://i1258.photobucket.com/albums/...ps362bde68.jpg
http://i1258.photobucket.com/albums/...ps8a3c7b77.jpg
http://i1258.photobucket.com/albums/...ps0e9d6545.jpg
http://i1258.photobucket.com/albums/...psf728309c.jpg
http://i1258.photobucket.com/albums/...ps6148a15d.jpg
http://i1258.photobucket.com/albums/...ps54198c0d.jpg

The software time will always be different than the actual machining time. This is because your software do not incorporate acceleration/decelaration in the timing calculation. Increase the acceleration and velocity in the Mach3 for all axes and you will get improved time.

Hi Khalid,

Actually I got it fixed.
The thing was that when I was creating *.TAP files, artcam has created in lines, insted in arcs.
When created in arcs TAP file, you get the speed you want, beacuse it creates circle with arcs, insted of godzillion little lines where machine cant get its speed up.
Machine was working awsome, untill the V groove wheel went berserk.
No I am putting linear bearings on all 3 axis.

Nice work

Switching to linear bearings on your z axis or the entire machine !? Xyz ?

Switching all 3 axis on linear bearings.
I got 2 sets of this for a bargain.
http://www.ebay.com/itm/2-Set-SBR20-...item3a732771d7

great price. how do you plan to mount the gantry and y-car to them?

20mm sounds very light for the MechMate weight.

It will need some modification to the Y-car, but I have started to design a modification on all axis.
@Axel:
I dont think is light, beacuse I think each linear bearing can widstand about 160 kg of force, and I plan to get 6 bearings on each axis, 3 of each side, even on the Z slide.
Majority of the weight of the MM is on the lower part of the machine, and I think its not more then 200kg of moving parts.
The biggest problem what I can think of is rack pinion and motor mounting, but this will have to be redone.

I understand. You may want to change for suported linear rails for some reasons I guess. The bearings can stand 160kgf, but what about the rails themselves ? Believe me, they can flex easily. Even in 30mm which are huge in front of the 20mm. I have both. My gantry is half the weight of the MechMate's. And I have changed my 20mm for some 30mm. The linear rail is hold every 175mm if I remember well. And with my gantry in motion, I could see the rails bend a bit between each screw. Otherhand, you need to have a dead flat surface to fix the rails, or they will bend on each irregularity of their base. Without loud pressure on one end whith the other one supported, you can bend a 3000x20mm rail of more than 50mm by hand. The 30mm is much more stiffer, and stays straight anytime. Just my experience to report if it can help. Instead of 6 by axis, you can order SBR LUU blocks, 4 will be better than 6 ;)

The are actually fully supported rails.
I would not take even in consideration without support :)
I went to 20 mm coz 30 mm was way too expensive.
Package:

2 X SBR20-2750mm 20 MM FULLY SUPPORTED LINEAR RAIL

4 X SBR20UU Motion Router Solide Block

Fully supported indeed, but maintained by a screw each 175mm. No problem in vertical motion, but it bends horizontaly. Whatever, even in 20mm it will be an improvement. I hope you'll get what you needed. CYA

Sorry Axel if i missunderstood.
Will investigate more of this matter.
Yes, I am thinking about the SBR20LUU, its much more stiffer.

Thanks

No problem marko. English is not my mother tongue too. The LUU are not that expensive, and they stays linear on 96mm long, it's a real improvement with this type of rails.

My idea of throwing 1 SBR20UU in the middle to keep the rail linear, and whole axis stiffer.
I guess I could go with 2 SBRUU on the outside and middle one can be LUU, what do you think about that.
I want to build a rock solid machine for aluminium as my work goes mostly there.
Once it happened that my 6 mm end bit run 2 deep into wood and my Y car buckled out of the V grooved wheel.
End bit did not broke.

Hmmmm. Aluminium... The MechMate is not a metal milling machine. All the Metal CNCs have prismatic linear rails, pretty expensive. What grade of aluminum will you machine ? Some can be very hard, some can be pittyful to machine.

Most of metal spindles are running very low too. Was your feed and speed correctly adjusted ? It may be the cause of this reject from the material. Some aluminium are very sticky and fill quickly the bit's helix that cause a reject too.

Anyway don't plan on the SBR rails to maintain the caddy if aluminium is able to raise it ! They are weak on an up load. Appreciating the weight of the caddy, it gives an idea about the forces to manage. You could install the rails in oposition, fixed on the sides of the gantry, but it will be a lot of modification of the mechmate's plates.

I don't think using a complicated combination of bearing blocks can help. In mechanics : use the right part, at the right place. Through, to align correctly 2 blocs is a long and serious job, they need to be aligned at 2/100e mm, it's close to be inpossible with 3 blocs. In my opinion, 4 long blocks by axis will be the best.

I dunno if a SBR system will be ok for aluminium. I guess not, they will be able to stand the forces during a short period, then they will deteriorate quickly. Otherhand with verry small passes it can be possible, but it's unsuitable if you want a production machine : too slow. The right part to stand metal milling, is 25 or 30mm linear rails type Hiwin or kind of. But it's 4 times the cost of SBR30 rails.

If you want to stay with SBR20 rails, which in my opinion is not suitable, the best you can do is to install your rails in oposition, and using 4xSBR20LUU for the gantry, and 4 TBR20UU for the caddie.

Anyway, keep in mind that linear rails are not as permissive as the Vgroove system to install. If the geometry is not finely adjusted, the motion may stick, and the bearings will deteriorate quickly : the ball circulation's groove is plastic remember. Plan on an align system with screws to fine adjust the rails and the blocks. You will need machinist measuring tools to install them : dial gauge, 0.05mm level, etc. MechMate is easy to build and install, these are not. I spent a lot of time to get mine correcty adjusted. The first four das was wasted. Good luck M8 !

Thanks for explaining this one, but I disagree about cutting aluminium.
The thing that pull up my Ycar was wood when 6mm end bit got stuck 2 deep with axle hitting the material.
To explain, I have cut small pieces more that a sq meter or aluminium 5000 series.
Strong aluminium to cut, and it was going pretty well with some lubricant.
I got my feed around 21 mm/s with stepdown 0.5mm but I belive I was shy about this one, and I did not have the proper end bit.
Lately I broke 2 bits and at the end I fugure out the that my rail and my wheel has lost its way.
I plan do modify the whole machine to cut mostly aluminium, and I will install a "screw" plate, to tighten material.
Also, I have installed bluemach probes, and with 5 min of your time, you can get Z anc hole circle probe with ease. (ping me if you need this one)
Here is a link my machine working on alu 2000 grade without lubricant.
http://vimeo.com/88204069
I am sure that alignment of the rail will be a pain, but not as much as my V groove wheels, because they were low quality, and they were not the same from each side, and were different each by each. So to align a machine with these kind of wheels was a pain.
This will be done with some carefull planning, but the stiffness of the machine will improve greatly.
I have also planned liquid nozzle and whole bunch stuff for the aluminium.
I will have some questions about this rail when they arrive, and hope it will be soon.
Here is the link of all of my aluminium work so far.
https://www.facebook.com/maister.cnc

Thanks again Axel,

Marko

Sounds like the quality of your wheels was more at fault than the design, but heck, half the fun is designing and building new stuff.
I applaud you for that, and will follow with interest.

I agree with Axel. The forces created with machining any metal are terrible on an unsuppported system let alone one that is designed for it. The profile rails offer better support for shock and load than the rails you are looking at. The option of preloaded guides ups the dynamic load rating as well. However there is a reason why a set of 1200mm rails and 4 guides cost $1700 USD for 30mm stock profile. But even with this, without a wear portion such as a brass gib to take the abuse they will deteriorate over time. I am only trying help you see that without a way to neutralize the uplift and harmonic shock on the gantry and y-car, you will still see premature failure. I wish you all the luck in your designing and endeavors but always look, listen to all people even those you don't agree with for knowledge can come from the least expected source and duly test and experiment for you will find a way if you truly desire it. Just don't break yourself or the bank in the process.

Another option, I am sure you have considered, would be to get a used bridgeport type mill and convert it to CNC. You could even reuse the control panel and switch it between the router and the mill.
Still it will be interesting to see how the modifications progress. Do post updates.

Thank you all, and I think this has gone in different direction then I intended.
Let me just say that I am very thankfull of this comments, beacuse I can only learn on them, and I am not trying to be hardheaded about this.
Basically I think there is a misunderstood the alignment of the rails.
What I think Axel is saying that it will positioned like on this picture:
http://www.cnczone.com/forums/attach...right-side-jpg

But I intend to align them on my I beam profiles to be something like this:
http://idea2reallife.files.wordpress...axis-sbr16.jpg

With that said, could there more pressure on the rails which are fully supported then on my V rails?
Also wanted to ask Axel why did you recommend the TBR instead of SBR bearings? Must be the quality, but cant find any good review and comparison.

Another thing to mention is that my I beam are pretty flat, and bolting down the SBR rails onto I beams would not be as much trouble, and there shouldn't be much vertical and horizontal bending.
Please, correct me if I'm wrong.

@Darren: Quality of the wheels is very low. There are not 2 of the same wheels and there is million modifications I had to do to make them work.

@DB: I did not think about this conversion, due the large surface what I really need. MM is a pretty good base for upgrading, and getting a large quantities machining area.
I will have a design ready in a couple of days and will post some picture for your review.

Together we can review the design and do the best possible machine. Actually, I am very excited about this idea :)

Marko

If going to linear guide rails for better performance I would suggest go hunting for 'real' linear guides.
http://www.mechmate.com/forums/showt...inear+bearings

yes, they are more expensive, but can be had cheaper on Ebay as well.Yes, mounting will need to be more exact ( can be done with leveling resin or such see CNC zone ) but that is what all professional machines use (and for a reason).

I doubt the ones your are going after right now will be worth the effort compared to the standard V-rails. They are kind of an in between solution, that is not worth it imo. I have SKF linears to upgrade mine, but decided to first use the V-rails, and my machine is not even finished yet ;-)