View Full Version : Rough Carving in Centerline
crowder888
11-29-2010, 07:49 PM
My machine has recently started carving rough and inconsistent letters in centerline. The result on the board looks exactly like the problem I had when my QC was shot (bit runnout). I'm running the CT and there are about 200 hours on the machine. Any help would be GREATLY appreciated. Thanks!
fwharris
11-29-2010, 07:55 PM
It could be a loose or out of adjustment Z truck bearing...
AskBud
11-29-2010, 08:15 PM
My machine has recently started carving rough and inconsistent letters in centerline. The result on the board looks exactly like the problem I had when my QC was shot (bit runnout). I'm running the CT and there are about 200 hours on the machine. Any help would be GREATLY appreciated. Thanks!
Things to consider, as we do not know your font, nor the size of the text.
Draw a circle and square, the same size as the text and use the same bit set at the same depth that the text was carved (look at you MPC and determine the deepest area for that measurement.
If you get the same result first consider the bit sharpness and the hardness of the board grain. Reduce the depth by half and see what happens.
The top of your "T" looks smooth, so I suspect the grain and hardness, the bit, or last, the "Y" movement of the truck.
It could also be the Font is too deep/strong for the size of the text.
AskBud
My machine has recently started carving rough and inconsistent letters in centerline. The result on the board looks exactly like the problem I had when my QC was shot (bit runnout). I'm running the CT and there are about 200 hours on the machine. Any help would be GREATLY appreciated. Thanks!
Another thing check your flex shaft, if it was not properly seated it will make the CT chatter. I assume you bought and install the CT and LHR sells the CT and truck, you might check to see if the rollers are loose on the truck like Floyd suggested. I would imagine the when it carved it made a lot of noise? I would start with the flex shaft to see if the ends are chewed up.
Ike
Digitalwoodshop
11-30-2010, 10:58 AM
The trick I use to get the bearings adjusted to the max closed position is to place a drop of nail polish on the nut flat closest to the drilled and tapped hole. THAT flat should be facing OUT when the bearing is at it's MAX CLOSED position... I think it is simply that that flat is NOT facing out and the Z Truck is Moving..... LOOSE BEARING.... Like posted above.
Ike... Not Chopped Liver..... but the Best Steak Money can buy.... Snicker.... Tag your it.... ( It's the Ike / AL banter...) Snicker...
AL
Well fine!! I am sure you are correct, but I have had this happen with a chewed up flex :)! Back to you Al!
Ike
Digitalwoodshop
11-30-2010, 02:08 PM
Ike, your correct too.... I have a broken flex on my bench.... I bet it was not cutting correct when it was partially broken and chewed up. Then a stall when it broke....
AL :)
It will be interesting to find out what it really is!
Ike
crowder888
11-30-2010, 06:20 PM
Well I took it all apart last night and checked everything. I couldn't make the truck wobble and all the bearings were tight against the rails. I cleaned it real well and put it back together. First carve was great! Second carve had the wobble again.
I watched a little closer the next time and found out that the rough carving is because the motor begins to "chug" every once in a while. When it runs smooth the carving is great, when it chugs the carving is awful.
I cleaned the dust bag thinking that was a problem...still chugging. Pulled the brushes and they look ok. Anything else I should check?
Thanks guys!!
bjbethke
11-30-2010, 06:31 PM
Well I took it all apart last night and checked everything. I couldn't make the truck wobble and all the bearings were tight against the rails. I cleaned it real well and put it back together. First carve was great! Second carve had the wobble again.
I watched a little closer the next time and found out that the rough carving is because the motor begins to "chug" every once in a while. When it runs smooth the carving is great, when it chugs the carving is awful.
I cleaned the dust bag thinking that was a problem...still chugging. Pulled the brushes and they look ok. Anything else I should check?
Thanks guys!!
Sounds like you have a bad motor bearing; mine just went out a week ago. The front bearing is coming apart.
earlyrider
11-30-2010, 06:34 PM
Howabout spindle bearings? I know its a new CT, but they are apparently rebuilding them with the older style Z truck. Maybe a loose bearing damper or?
Ron
Digitalwoodshop
11-30-2010, 06:46 PM
How many Cut Motor Hours? Sounds like the Y Truck Gear Box Bearings? Any Clicking when the head goes to the Bit Plate?
Like Ike said.... Pull the Flex all the way out and inspect it then flip it end for end....
Dull Bit? I use a diamond file to touch up the V Bits after cleaning. Makes a difference.
If a front bearing in the motor is going bad then the armature is dropping and scraping the inner stator.
Just a few more ideas.....
AL
crowder888
11-30-2010, 07:01 PM
There are about 200 hours on the machine. I have not noticed any clicking when going to the bit plate. I did pull the flex shaft and checked it for damage....none, but flipped it anyway. The bit is brand new (I also use the diamond file to touch them up frequently). I might have to tear into the motor and check it out.
The chugging comes and goes like a sine wave. At a certain frequency and it purrs pretty nicely but then it get progressively worse....repeat etc.
Did you check the flex shaft? Make sure it is seat in the motor and the screw is tight and seated in the chuck. Plus check both ends to see if it chewed up or bulged end. If it is not seated properly it tears it up. Ok then turn the chuck and make sure you feel resistance, if you turn it half way to the right and release, it should spring back. Check the heat in the flex I had one go bad in the middle. You might wait to give it a good moly lube
Ike
crowder888
11-30-2010, 07:57 PM
Flex shaft looks ok. Springs back just like you said and is barely warm to the touch. I did go ahead and lube it for good measure. Thanks!
I think then you need to change the brushes especially since you are getting power fluctuations. How much magnet is left better yet how round is the bottom. I had to replace mine and I thought they look good. I was having quite a few check cut motor errors until I replaced them.
Ike
Digitalwoodshop
11-30-2010, 10:05 PM
Ike... You bring up a good point... The power of the Magnet.... on the Cut Motor Shaft that makes pulses with the RPM Sensor... I remember someone flipped one changing the polarity and it made a difference.....
I have preached that the Check Cut Motor at the beginning of a carve is a Compiler Problem with the upload of Designer to the Card. A speed window for a given function... Carve Centerline or Raster Cut a pattern....
Recently I did 3 of the same projects and the first and last did the Check Cut Motor and stopped... The Middle one did NOT..... That Confused me... If it was a Compiler Problem... Then why WORK the 2nd time... That blows holes in that theory....
What "IF" it was a weak magnet? And Flipping it or replacing it would solve the CCM problem.... Another ERICKA Moment.... That is why all the Program Updates never fixed it..... It was NOT a Program problem..... Just another Quirk... A weak Magnet....
Next time I dig into the Cut Motor I will Flip the Magnet.... Add this to the list of "AL was Wrong.... List"..... If I was issued a Service Manual with Wiring and Block Diagrams with Circuit Descriptions like Military Service Manuals then I would be further ahead. Should write one.... But with bad theories... Could lead someone astray...
With a Pin Out of the DB-25 Connector on the machine I bet I could make a Talking Module like the Tool Talker. The Tool Talker has gone on the back burner for me too....
AL
crowder888
12-09-2010, 12:38 AM
PROBLEM SOLVED!
Replaced the brushes tonight which fixed the motor problem I was having. Still had some rough lines in the carving though. After watching a little closer I noticed the belt was a little loose and the teeth would catch slightly before they sat in the gear causing a jerk in the Y motion. Tightened the belt and the quality was 100% better.
Thanks guys for all the help!!
Mike
PROBLEM SOLVED!
Replaced the brushes tonight which fixed the motor problem I was having. Still had some rough lines in the carving though. After watching a little closer I noticed the belt was a little loose and the teeth would catch slightly before they sat in the gear causing a jerk in the Y motion. Tightened the belt and the quality was 100% better.
Thanks guys for all the help!!
Mike
Great news Mike, you still might want to watch the Y motor gears, depending on how worn it has become. A good test is with the power off, that has been off for a little time. By hand move the truck to the bit finder until you engage the plate. If it travel smooth then the gears are working correctly. If not it could be saw dust so use some air to clean out rail and gear area and repeat. Another good idea is to take a cloth and clean the top and bottom rail where the rollers of the truck travel.
This is also a good test to see if any wires have moved. If you have smooth travel the it was most likely dust build up. If not you may need a new Y motor gear or the whole unit. Sorry I know you said all is well! I been there too and all was well for a few more carvings and well we all the rest of the story!
Ike
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