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View Full Version : Need Help! CNCRP PRO - Rail Issues



vinsonelt
05-29-2014, 11:19 PM
Ill do my best to describe the issue I am having with the rails on the CNCRP PRO machine.

When unboxing the rails I noticed they were bowed and twisted. I thought that after installing them in the vcon linear motion clamps onto the table base it would fix the issue. Unfortunately that has not happened. I also noticed that at least one side, sometimes two, and on one rail three sides of the rail had dents or rust damage. I unfortunately did not realize this tell after I had installed the rails and was rolling a carriage down the axis and felt the bumps, so I had to remove than reinstall a few of the rails. Something to watch out for on your build, look each rail over closely and pick the best of the four sides to use for the rolling surface.

I installed the rails per the tips and tricks of the cncrp website, I am confident that the rails are seated properly in the clamps.

I noticed the issue when my carriage would not roll smoothly down the entire length of the track. When the carriage rolled smooth all the wheels made good contact on both sides of the rails. When I started feeling resistance I could see one of the wheels loose contact with one side of the rail and just press tightly against the other side. This indicated the rail was bowed out, and was probably the reason for the resistance.

I have checked with a laser level and a machinist level, the rail is very level.

In the video I have very lightly clamped a level (just for a reference straight edge) to the vcon rail. I placed a bright light behind the level and rail to see how straight the rail is. I saw gaps of .02" using a feeler gage in two spots, and these were the spots I was feeling the resistance. Most other portions of the rail were within .002". The video is not fancy but helps show my issue with the rail.

http://youtu.be/niy44jh_FgQ

In this picture I was checking to see if the van clams were level vertically, I checked under the level with a .002" feeler gage and the level was contacting each clamp.
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checking the rail level with a laser
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Finally checking the rails horizontal alignment.
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The level is butted up to the inside of the vcon clamps. They seemed very close on most all the claps with the exception of the clamp that is closest to the .02" deflection. It was just slightly off.

Anyhow- Something I did notice - when the gantry is installed the resistance was minimized to some extent. The extra weight of everything changes how the resistance felt, and things seemed to roll more smoothly. You could still feel a little bit of resistance in the one spot and the wheel would still loose contact with one side of the rail.

Thoughts Solutions? Any Help would be extremely appreciated. Is this even an issue?

Thanks You

ahren
05-30-2014, 01:58 PM
Hi vinsonelt,

This doesn't sound too severe, but we can send you another V-Con clamp that you can use to shim underneath the area that appears to be sagging. Shoot us an email and we can get this going for you. We should be able to get this out to you today.

Best regards,

Ahren
CNCRouterParts (http://www.cncrouterparts.com)

FoxCNC1
06-01-2014, 12:00 PM
You need shimming to build this machine. I would also add, that overtime the steel should get better (once its broken in).
But once you get it working you will be happy - Arhen and his team are great guys and a good company with good support.

vinsonelt
06-18-2014, 10:17 PM
I am stuck and do not know what to do. I am having serious issues with these rails. The more accurate tools I buy and the more parts I buy the bigger the problems I see.

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I have purchased two more vcon clamps for just this one rail and the issue has gotten a little better but I still have inacuracies of .008 in the height of the rail. In the first image I tried to level the vcon clamps. I had them leveled down to .0015" than I tightened them down to the extrusion, remeasured and still better than .0015" . Next I put the cold roll steel rails in, put wood clamps on each vcon clamps and cold rolled steel rails (some portions of the steel required 550 # irwin wood clamps just to get them to seat in the vcon clamp) then i tightened down the cold roll steel rails into the vcon clamps. Got my new straight edge (certified to at least .003" over the 50" run) and my trusty feeler gauge..... .012" off on numerous points along the rail. The vcon clamps were all level with in .002" from one another...

Next I loosened the vcon clamps, and clamp the cold roll steel rail and vcon clamp to a piece of square tube steel (seems to be as flat as my straight edge) and tighten the vcon clamps. measure .008" gaps!!!!! I do not think that I have any more adjustment space between the vcon clamp fasteners and tslot in the extruded aluminum. I am at a loss what to do . I can not raise the vcon clamps in the area that needs to be raised and I can not lower it in the areas that need to be lowered.

The pictures of the spoilboard surfacing show the results of the issues I am having with the rails on my machine. The ridges are .016" as some spots, than at others the surfaced area is as smooth as butter.
If anyone has ran into this issue and knows a fix I would really appreciate some advice.

FoxCNC1
06-18-2014, 10:38 PM
is your Z axis tight? sometimes it mine needs to be tightened.

ahren
06-19-2014, 08:53 AM
Thomas,

We'll give you a call later today to sort through this. You shouldn't need that much force to seat the rail, so it may very well have an issue. If that's the case we may need to replace the rail. If there is a slight bow to the rail, it should be installed so the bow is "up" in the middle, and this can usually be seated in the V-Con with minimal pressure, but that doesn't sound at all like what you are experiencing. We'll get this taken care of regardless -- we want you to have a good experience with your machine. In general, feel free to contact us directly with build issues and we are happy to help.

Best regards,

Ahren
CNCRouterParts (http://www.cncrouterparts.com)

vinsonelt
11-24-2014, 11:12 PM
It has been a long while since I last posted on the site. We now have two kids, so I rarely see me beloved machine let alone get to use it. I think I solved all the rail issues with the new rails that I was sent and some shim stock. The machine has sat idle with the exception of a few foam planes I have cut out and some small engraving projects.

Accuracy issues:
I have been seeing some strange accuracy issues with some of my projects. Some of the cuts are spot on .003" to .0005", and I am more than happy with that. But for some reason on the same piece I am having error of .032" on a 3" cut.

I have attached some pictures of the most current work piece. The finish of the part out of the machine is really nice, looking at it you would think it is perfect (and for this project it works just fine) yet when you get the calipers out you can start to see issues.

All the cuts that I have detailed in the images were pocket cuts, with the exception of one profile cut that cuts the piece out from the stock. This profile cut seems to be the main issues.

Any ideas?

I could do some more test cuts is that would help.....

Thanks

ahren
11-25-2014, 12:38 AM
Thomas,

I just sent you an email -- you could be experiencing some deflection during the profile cut. This can potentially be solved with some mechanical adjustments and cutting parameters, but in looking back at your order history I see you have the older version of our PRO 4x4. We made some significant upgrades to the riser system in early 2014 that stiffen the entire system, and have upgraded several customers to these components. I think this could address some if not all of the errors you are seeing -- we'll give you a call to discuss in the morning.

Best regards,

Ahren
CNCRouterParts (http://www.cncrouterparts.com)

vinsonelt
12-10-2014, 04:00 PM
I was able to solve a lot of my problem, it seemed that I had some loose connections. I went over the entire machine again and snugged everything down. I found a few loose bolts that connect the front of the router mount to the back portion of the router mount. This seemed to bring all the error down to <.01 ish. For the size of this machine I am happy with that. I don't need it to be any more accurate for the things that I am cutting.
It was nice that the staff form CNCRouterParts got back to me quickly and were there to help.

FoxCNC1
12-10-2014, 10:03 PM
It has been a long while since I last posted on the site. We now have two kids, so I rarely see me beloved machine let alone get to use it. I think I solved all the rail issues with the new rails that I was sent and some shim stock. The machine has sat idle with the exception of a few foam planes I have cut out and some small engraving projects.

Accuracy issues:
I have been seeing some strange accuracy issues with some of my projects. Some of the cuts are spot on .003" to .0005", and I am more than happy with that. But for some reason on the same piece I am having error of .032" on a 3" cut.

I have attached some pictures of the most current work piece. The finish of the part out of the machine is really nice, looking at it you would think it is perfect (and for this project it works just fine) yet when you get the calipers out you can start to see issues.

All the cuts that I have detailed in the images were pocket cuts, with the exception of one profile cut that cuts the piece out from the stock. This profile cut seems to be the main issues.

Any ideas?

I could do some more test cuts is that would help.....

Thanks

Glad your machine is working better.
what program did you use for the measurement graphic?

vinsonelt
12-10-2014, 11:01 PM
Thank you,
I just used Microsoft paint. I took all the measurements with some digital calipers and added them and the lines to a picture I had taken in paint.