We had big issues on the beginning with Roland 52 DC. After sending mill back to company and sending it back to us, in the end they told s it was mill issue and they updated it for us to 52DCi which resolved problem. I think that something you should mention. we had technician coming on side and trying to fix it, it was just huge headache with that mill. Toland 52 Dci we haven't experienced issues like that.
With that being said, we also had those lines showing in the middle of the crown, and we also had Roland 50 at some point and we had that at both mills. What we did (summarizing whole story):
- turned out we were using wrong tools. We decided to go straight to Zahn company and buy from them again as no other tools where ever good
-made sure that correct tools where chosen in Millbox when creating case( it does make it a difference you choose Pmma tools to mill zirconia crown - they are not the same)
- if you have no issue running calibration (as calibration doesn't stop and doesn't give you errors) then calibration you are running is fine.
- if you had sent mill to them and they did calibration on their side, then at this point you need to "believe" them. They can always send someone on site to run calibration as well (they also mill block in wax puck) and you can see if they are actually getting good results
- spindle or collet may be an issue. How many hours you have on the spindle, and how does the collet looks like? How long have you been using collet, how does it look like?
-x,y,z axsis - we had that issue on Roland 50 where wires were loose. But our Roland 50 was old, and reeeeeeealy overused. You will always have some line on crown, question is how much are you getting?
Feel free to message me as I had to figure out everything and it took a while, but I am not having any issues now.
I think most of this has been addressed earlier in the thread, I believe we have looked at essentially all of these factors. In regards to "believing" in them, they are doing their test on soft wax and when we got them to send a picture of milled zirconia the parting line still exists. I don't trust someone who is checking the quality of milling using wax. Also when they send me a picture of zirconia with a parting line and tell me that's good, I also don't believe them because I can see that it is not. Also I have about 10 years experience working with Rolands and I don't ever recall these types of results "acceptable". I was generally not the actual mill operator though so my actual experience in trouble shooting and diagnostics is a little lacking.
I have gotten more involved in the current situation because the mill operation got changed from the lab owners son to a tech who actually cares. My observation is that the mills have not been properly maintained while being operated by the previous person and now that I have someone to work with who will actually do troubleshooting and maintenance etc. we have an opportunity to get things straightened out. Also I wasn't generally seeing our milling results before but I had to pop in after hours to cut a bridge out and put it in the sintering and that's when I realized that our milling wasn't acceptable.
an End Switch or Limit switch refers to a small switch on both ends of any linear axis, for example on the X axis which is linear, it detects the furthest limit the axis can move. if the machine moves all the way to the end and is still being given a signal to continue moving it can push itself too far and in a belt driven system like the old Rolands this can mean the belts get worn prematurely. even worse, the machine wouldn't know when to stop and go back.
every machine should have an indication system that the linear axes have reached their effective end of range of motion. this makes sure the machine doesn't crash and can read the length of its travel and do the internal arithmetic that keeps the work envelope properly known and all the home and idle positions known. everything is based on the length of travel of each axis. if you command the machine to move 3mm in x, it should know that if it moves this 3mm it won't hit the limit.
Thank you, I was wondering if it was something along these lines but a quick google search wasn't very helpful and my workload has been ridiculous so I wasn't able to dig deeper
For a small update on the problem: We had to back off the diagnostics a little to keep production going. We did a lot of info gathering and picture taking, ran some calibration tests, weren't seeing any definitive results so we sent all the information in a detailed email to a manager at Zahn who is aware of the issue we are having. He wasn't able to figure anything out from that information and told us they had set up a meeting with Roland about what's going on. We have not heard whether this meeting has taken place. In the mean time we did get a new table built for the mills because it came to our attention that the table currently in use wasn't stable enough. We got the new table set up today and while it hasn't gotten rid of any issues, it does appear to have improved the rough areas/chipping issues.
I have concerns that some of this could have to the previously mentioned suspected lack of maintenance for an unknown time period. (there was some maintenance, but minimal)
Are the lines with every milling system or mostly roland?
We are only using rolands so I don't know. I would assume they are possible on any mill.
Sorry if this response seems a bit grouchy, it's the end of another very long day