Hi, I'm starting a new thread to discuss some issues I've been having with the spindle on my new SVM2. I want to say right from the outset that I'm still very impressed with the machine, and that I think that the problems I'm seeing are more than likely related only to my machine. So don't jump to any conclusions that what I'm seeing is a rerun of the Mikini saga, it's not.

So, there are two issues I've been trying to get to the bottom of,

One is that my spindle was having trouble rotating under no load below 500 rpm, and it had low torque at that speed, and it would stall completely at 300 or so rpm. These rpms are the S entry in mach3.

The second is that every now and then, the spindle speed would drop down in revs for a few seconds then recover.

Now, I'm a newby at setting the correct speeds and feeds, and I have a lot to learn, so I have been using gwizard to suggest the correct ones and after the first couple of incidents I've been using the feed rates rather conservatively. What I found was I could not get anywhere near the feed rates suggested, and I almost always had to increase the spindle rpm to get the chip load down. So I started using the endmill manufacturers calculations and I found they generally lined up with Gwizard, which left me wondering if the machine was actually doing what the G code told it to. The short answer, is no, it was not doing what it was told to do.

So, I spent a day reading the mach3 manual and checking what settings had been put into mach3, to make sure they were still what the manufacturer supplied, and they made sense. They were still the same, and they made sense, as best I can tell anyway.

There were several other issues that appeared once I started running some fairly basic tests. The most alarming was that when in mdi mode and running the spindle at or below 500 rpm random characters started appearing in the input field. These seemed to include the enter key, as they would be submitted as command and mach3 would give error messages. Then the home button was pressed ( not by me, from who knows where ) and the machine homed itself unexpectedly. The other issue is that the spindle developed a knocking noise, if it was a petrol engine I'd say that it had a big end knock. I took the belt off the motor, which confirmed that the noise was coming from the motor, not the spindle itself.