Z-axis Problems

[GrandpaB]

Hello Shark Men,

I purchased my Shark HD over a year ago, and due to family medical issues, and the typical learning curve I have not yet gotten it into a production mode. I have solved a number of problems along the way. One non-problem that I chased after reading a post on the Shark Forum was a concern that the CNC bed might not be coplanar with the XY plane. I’m happy to report that it was out by no more than 0.022” which is accurate enough for the types of projects I will be doing. I have resolved the material clamping, material flatness, speed and feed, and VCarve design issues.

The one remaining problem that I am encountering is that the Z-axis is frequently cutting too deep. One of the primary uses for which I purchased the Shark is to cut toy car bodies from 2” x 4” yellow pine. Earlier this week I attempted to cut 12 bodies out of two 13” boards. There was no problem with the first board, however the cut was so deep on the second board that it broke, one of the bodies came free, jammed the router and blew a fuse. After the first board was cut, I removed it, clamped the second board in its place, and clicked run. The XYZ0 was not altered between the two runs.

The axel and window holes are cut through the 2” x 4” into a sacrificial board and the body profiles are cut leaving 0.100” of material. In a secondary operation the bodies are cut free from the board on a router using a 1/8” round over bit. This secondary operation serves two purposes; it cuts the bodies free and rounds over the edges on the bodies.

I have experienced other instances where the router has cut too deep, but I had attributed it to other causes like the CNC bed not being coplanar, the 2”x 4” being warped, the board clamping not being secure, or something in the job setup being incorrect. In this case the two boards were flat and the clamping was secure. I have read in the Shark Forum of other owners who have experienced similar problems that were caused by poor electrical connections.

The X, Y, and Z cable connectors are tightly screwed into the back of the control box. I have attempted alter the Z0 setting by jogging the Z-axis, but Z0 has not changed.. Can you suggest what the problem may be and how I might resolve the issue? Thanks in advance for your assistance.

[drueth]

GrandpaB

Looking at the pic. you have posted it looks like you are using a .025 or greater Up cut EM bit, with a pass depth of about 0.25 . With a cut that deep I am sure the path will fill up with chips and maybe pulling the bit or router down. It also may be causing the router to loose place when it tries to pull the bit up to begin the next pass. I would try severial thing to see if you can get around this problem. Back off on the pass depth. yousing a wooden stick and your shop vac suck the chips out of the cut as the machine moves about. Be sure your router is not being pulled down in the clamp. Be sure the bit is not being pulled down. When the machine is done the cut . from the control pannel jog the bit to Z zero is it going to deep????

You could also do the cut in two tool passes. You would set the first tool pass to say a cut depth of 1" . When the cut is compleat clean out all the chips and do a second pass with a start dept of 1" and a cut depth of 1" (the sum of start depth and cut depth are the total depth of cut ) . Or you could just pause the cut after the bit pulls up stop the router clean out the cut and continue from there.

Good luck.

[Eagle55]

I agree with drueth, that I see indications of stress and pressure that is likely flexing the gantry. The upcut spiral should be clearing the chips as they cut but the pass depth is a little bit much for what I think I would do. Depending on the material and speed I try to cut, I normally use pass depths of .100 or less. If I find that it is doing fine I might increase the FRO speed slider a little to cut faster. (ie I usually design so that I can cut at about 50% of design speed, then If I want it to go up I can or down if it is too fast. What I would expect to see is a smooth cut the width of the car, and not the definite "layers" like I see. I thought at first it was 1/4" ply stack up and being cut. I think I would also put a backer of say 1/4" ply and cut all the way through and use a couple of tabs to hold the car in place. (say about .15 thick and 1/4" long just so I could make sure they don't get free of the material and cause what they did for you.

Roger

[ohiococonut]

I have to agree with the other two gentlemen. I cut a lot of toy cars out for my grandsons out of 2 bys and learned by experience your cutting depth is too aggressive, especially for the Shark, there's simply too much flex. I limit my depth to .1 and speed up the feed rate to keep from burning the pine. I also use a spoil board and add tabs. And, even using a Shark tank I still have to leave the front open and use my shop vac to suck out the chips while cutting.
It may take a little longer cut but it saves time on my oscillating sander cleaning them up.

[SawDust913]

I agree with both the other guys. Using a .25 end mill router rpm 16,000 and cutting speed 80 inch per min with cutting depth of .09 and using the shop vac to keep the sawdust from building up. (this I know will break a bit when not done) Opps! another piece of carbide gone. This seems to work with oak using the Shark Pro Plus HD. Too big of bite not only slightly bends the bit but the gantry will flex. Oh yea! Myself I prefer to leave about .0625 from the bottom then using a dremel and a .125 chipper bit to cut the pieces out, it's less sanding then using tabs. Don't that scare you not having a sacrificial board under the work piece?

[creek]

Have had my CNC HD 2.0 Shark for a little over a year mostly the issues is the user problems due to learning curve. I now have problem that has not occurred to me before. The |Control Panel Version 2.0 with Virtual Zero will not power on? Have removed all cables and re-seated everything. Waiting on reply from Next Wave now. Has any one had this issue before. Have not opened the control panel yet? Is there a interanl fuse I may have blown?
Any help is appreciated.
Thanks
creek

[Kevink18]

There is a fuse right by the power in and I believe there is also one internaly.

[creek]

There is a fuse right by the power in and I believe there is also one internaly.

Thanks Kevink18 I will look when I get home today. Once again thanks for the help.