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  #211  
Old Mon 02 December 2013, 15:10
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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
Attached Files
File Type: dxf Santa's Reindeer.dxf (113.2 KB, 44 views)
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  #212  
Old Mon 02 December 2013, 16:15
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
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Tks for sharing
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  #213  
Old Mon 02 December 2013, 19:38
lonestaral
Just call me: Al #114
 
Isarn
Thailand
Send a message via Skype™ to lonestaral
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.
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  #214  
Old Thu 12 December 2013, 18:11
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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.



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.






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  #215  
Old Thu 12 December 2013, 19:45
Kornerking
Just call me: Pete #127
 
Big Falls, Mn
United States of America
Great pics. Well at least the first 3.
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  #216  
Old Fri 13 December 2013, 05:29
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Were those pics focused on the reindeer or Santa's Helpers? Ha Ha. I bet you hands are a bit sore from tapping.
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  #217  
Old Fri 13 December 2013, 05:35
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
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?
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  #218  
Old Fri 13 December 2013, 05:51
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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?
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  #219  
Old Tue 11 March 2014, 05:51
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
Long time no see.

Some recent photos.
Im switching to linear bearings coz the solution ov V groove rollers is bad.










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  #220  
Old Tue 11 March 2014, 07:21
Khalid
Just call me: khalid
 
Sadiqabad
Pakistan
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.
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  #221  
Old Tue 11 March 2014, 07:25
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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.
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  #222  
Old Tue 11 March 2014, 14:54
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Nice work
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  #223  
Old Tue 11 March 2014, 16:24
Fox
Just call me: Fox
 
Amsterdam
Netherlands
Switching to linear bearings on your z axis or the entire machine !? Xyz ?
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  #224  
Old Tue 11 March 2014, 16:27
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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
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  #225  
Old Tue 11 March 2014, 16:34
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
great price. how do you plan to mount the gantry and y-car to them?
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  #226  
Old Tue 11 March 2014, 16:37
Axel1966
Just call me: Axel
 
Paris
France
20mm sounds very light for the MechMate weight.
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  #227  
Old Tue 11 March 2014, 16:51
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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.
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  #228  
Old Tue 11 March 2014, 17:17
Axel1966
Just call me: Axel
 
Paris
France
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

Last edited by Axel1966; Tue 11 March 2014 at 17:19..
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  #229  
Old Tue 11 March 2014, 17:21
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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

Last edited by marko cro; Tue 11 March 2014 at 17:23..
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  #230  
Old Tue 11 March 2014, 17:50
Axel1966
Just call me: Axel
 
Paris
France
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
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  #231  
Old Tue 11 March 2014, 17:56
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
Sorry Axel if i missunderstood.
Will investigate more of this matter.
Yes, I am thinking about the SBR20LUU, its much more stiffer.

Thanks

Last edited by marko cro; Tue 11 March 2014 at 18:03..
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  #232  
Old Tue 11 March 2014, 18:10
Axel1966
Just call me: Axel
 
Paris
France
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.
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  #233  
Old Tue 11 March 2014, 18:13
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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.
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  #234  
Old Tue 11 March 2014, 19:11
Axel1966
Just call me: Axel
 
Paris
France
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 !
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  #235  
Old Tue 11 March 2014, 19:38
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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

Last edited by marko cro; Tue 11 March 2014 at 19:40..
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  #236  
Old Tue 11 March 2014, 20:14
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
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.
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  #237  
Old Tue 11 March 2014, 21:34
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
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.
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  #238  
Old Tue 11 March 2014, 22:25
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
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.
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  #239  
Old Wed 12 March 2014, 08:19
marko cro
Just call me: Marko #107
 
Dakovo
Croatia
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:


But I intend to align them on my I beam profiles to be something like this:


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

Last edited by marko cro; Wed 12 March 2014 at 08:26..
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  #240  
Old Wed 12 March 2014, 11:32
Fox
Just call me: Fox
 
Amsterdam
Netherlands
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 ;-)

Last edited by Fox; Wed 12 March 2014 at 11:37..
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