|
Post by aaron1869 on Aug 6, 2018 20:43:13 GMT -5
In the past I’ve had problems burning 1/8” Ball Nose Bits. I’ve posted questions on the forum and was told to use a chip load chart. I contacted Whiteside and was sent a spreadsheet that calculates feed and speed rates. This last 3D carving was 24x10x1.25. For the roughing pass I used a 3/8” end mil. This went real well. The problem was with the finishing pass. I’m using a 1/8” conical Ball Nose with a feed rate of 120 ipm and 10,000 rpm. This is the first time I’ve used a feed rate greater then 90 ipm. From what I have been told on the forum and using this spreadsheet 120 ipm is correct. In less than 3 minutes the bit was pulled down through the 1.25” and shutdown for an overload.
Why was the Z-axis not able to hold the correct position? I brought the bit back to the top of the wood and the controller indicated a Z height of 25.0. I had the machine return to home and then placed the bit back to my reference position and Z height now indicated 0.
Is there a feed rate limit on the Pro-6 or is there a problem with my Z stepper?
|
|
|
Post by RetiredAFChief on Sept 4, 2018 19:56:47 GMT -5
In the past I’ve had problems burning 1/8” Ball Nose Bits. I’ve posted questions on the forum and was told to use a chip load chart. I contacted Whiteside and was sent a spreadsheet that calculates feed and speed rates. This last 3D carving was 24x10x1.25. For the roughing pass I used a 3/8” end mil. This went real well. The problem was with the finishing pass. I’m using a 1/8” conical Ball Nose with a feed rate of 120 ipm and 10,000 rpm. This is the first time I’ve used a feed rate greater then 90 ipm. From what I have been told on the forum and using this spreadsheet 120 ipm is correct. In less than 3 minutes the bit was pulled down through the 1.25” and shutdown for an overload. Why was the Z-axis not able to hold the correct position? I brought the bit back to the top of the wood and the controller indicated a Z height of 25.0. I had the machine return to home and then placed the bit back to my reference position and Z height now indicated 0. Is there a feed rate limit on the Pro-6 or is there a problem with my Z stepper? Take a moment and ck your Z axis coupling. I had a similar problem when I first got my machine and it turned out my coupling was not connected properly. I also had a pinched wire in my Z axis sensor by the coupling. I put the coupling back where it should be and made sure I tightned the set screws and un pinched the wire and made sure I didnt pinch it again when I put plastic cover on and have had zero problems since. I have a post similiar to yours in this forum that might offer more help than this...
Good luck..
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Sept 5, 2018 8:18:19 GMT -5
The mechanical systems can be a problem, loose couplers or wires, or the bit will slip in a dirty collet, or your plunge rate might be off. Each bit has two motion parameters, the feed rate which is for X and Y and the plunge rate which is for Z. All bits will plunge slower than feed because they don't have the ability to clear chips as quickly going down, that's why ramping is important even for center cutting bits. Drills, on the other hand, can't go in X and Y as they have no side cutting ability so their feed rate is really the plunge rate. While your bit may feed at 120 ipm it will likely plunge somewhat slower, perhaps 1/2 to 1/4 that rate, but again your toolpath and other things affect that rate. If you try to plunge too fast you may lose steps because stepper motors have less torque as you go faster. While an up cut bit may pull on the Z axis and lose steps, a tapered bit is less likely to do this than a normal bit as the flutes and thus the pull it can exert also tapers from the shank to the tip. When calculating speeds and feeds for a tapered bit you base the numbers on the tip size and not the shank size.
You didn't say what your axial or radial depth of cut was for the finish pass. Normally people will use 7-10% step over so they don't have much in the way of scalloping. For a 3D carving I don't like to leave a lot of stock for the finish pass so that I can go faster, so I might go with 0.06" or so but certainly less than 0.1".
|
|