My 1610L and it's issues

[allenj20]

Update: My spindle definitely has the RPM dip at under 1k RPM issue. Is there a known fix for this besides replacing the speed controller for a fifth time?

Should I just keep it above 1k rpm and not worry about it? It's probably indicative of a growing problem or general design flaw.

Should I send it off to the ACS industrial chaps and see what they can do with it?

Should I start speccing out a AC motor and VFD?

One thing that concerns me with the AC motor and VFD is the AC motor will probably weigh more than the BLDC motor and I bet the Z axis stepper is probably only just able to handle the weight it has. Also at that point I am not sure about keeping the control panel or anything else except the steppers and stepper drivers which seem decent. But that's probably a step in the right direction anyway getting rid of the Mikini electronics.


Anyone in Colorado want to buy a Mikini or trade for a Tormach?

[mcphill]

I cut steel for the first time today, I have issues too... I was running at 1000 RPM. In a 90 second process, it dipped to 800 three times. I ran the same program over an over, and it would repeat 2 or 3 times every cycle. At my intended DOC it stalled the spindle when it dipped. I slowed the feedrate about 1/3 and it didn't stall any more.

I then changed to a full depth cut, 2000 rpm, .75 FEM, 1.5 DOC, 0.02 WOC. It handled this well. I did that pass over 10 times and it never stalled. It ran up to 65% load, but kept on chugging. It never dipped in speed either.

Not sure what to do, I think I will give Phil a chance to techno-babble me on how the machine is fine but I did something wrong...

[SWATH]

Sorry about your problems, there doesn't seem to be any sort of fix other than replacing the board (which may or may not work as I think it is a systemic board problem). I would definitely take it up with Phil first, even if he gives you a line about your ground line or something, at least make him aware that there is a problem. I would also then call ACS and ask them how many mikinis they have serviced and and what problems they find with them.

My replacement board no longer has any dips in rpm at any speed however it has other problems now. Someone else has indicated that a new revision of the board is in development but won't be available for another year or so. At least make Phil aware of this common problem, I think the only way to convince them that the problem is with the board and not our power or ground lines or that we don't have enough rosaries hanging from the jog pendant is if enough of us complain and hold their feet to the fire.

[allenj20]

The thing about taking it up with Phil is I have been taking it up with Phil for going on 3 years now with no real results. I mean the spindle does at least start for now which is an improvement but it's still a dodgy spindle.

The other thing is I don't believe for a second that Phil doesn't know there is a problem with the spindle boards. He's been shipping failure prone spindle boards for three years now. Trust me, he knows there's a problem. I have had this conversation with him many many times by now and so has most of the Mikini owners on this board. It's not news by now I am sure.

The whole power thing is just a stall tactic. What I can't figure is what is he stalling for. He's had three years which is plenty of stalling.

I know some of you guys are still in that hopeful phase. I was once there myself but understand I have been waiting on a fully functional machine since 2009 so I am way over that by now.

The only recourse I see with Phil is an attorney. And though in this case it is probably entirely justified that is not generally my style.

So I think I am going to go the Cowboy route and do a VFD and AC induction motor swap out.

Based on weight I don't think I can do a 3 HP motor I think it would be too heavy. I am thinking I can do a 2HP motor probably. But really I don't think we are really getting 3 HP out of the BLDC motor anyway so I don't think I will really be losing out there.

This is what I am thinking about getting comments and feedback desired.

http://www.driveswarehouse.com/docum...chi/WJ200B.pdf

Surplus Center - 2 HP 1725 RPM 208-230/460 VAC 3PH MOTOR

Anyone got any advice on engineering an AC motor VFD replacement package?

Sorry about your problems, there doesn't seem to be any sort of fix other than replacing the board (which may or may not work as I think it is a systemic board problem). I would definitely take it up with Phil first, even if he gives you a line about your ground line or something, at least make him aware that there is a problem. I would also then call ACS and ask them how many mikinis they have serviced and and what problems they find with them.

My replacement board no longer has any dips in rpm at any speed however it has other problems now. Someone else has indicated that a new revision of the board is in development but won't be available for another year or so. At least make Phil aware of this common problem, I think the only way to convince them that the problem is with the board and not our power or ground lines or that we don't have enough rosaries hanging from the jog pendant is if enough of us complain and hold their feet to the fire.

[SWATH]

I feel your pain but I haven't quite given up hope just yet. I think you could use a 3hp motor as long as you put some stiffer gas struts on there to compensate for the added weight, there is a wide variety at McMaster-Carr, I assume you would just need to make the head "neutrally bouyant" or slightly less. The motor you link would give you a bit hit on RPM unless you ratio'd the pulley. Let us know how it goes, maybe start a new thread about your conversion.

[MichaelHenry]

Have you guys looking for 3 HP spindle solutions checked to see if you would commonly need that much HP? Maybe you do, but if not there might be a price to pay for buying more HP than you need.

[allenj20]

Update on my mill. Last weekend I was making this test part.



out of 6061 T6 Aluminum and periodically the spindle would momentarily shut off. The light tower would go out and the spindle would stop and then restart. Just for a fraction of a second really but obviously this was a problem. It was still also dipping as well below 1000 RPM.

So I was trying to figure out what to do. I was pricing a VFD setup a new Tormach etc... Finally I decided to take a crack at figuring out the electronics problem myself. I figured worst case I fry something I was going to replace with the VFD setup anyway. I figured it was either the Spindle control board or the main board based on what slowtwitch saw with his main board and a bad reflow Mikni repair.

So tonight I started with the main board I took all the boards on the control panel and inspected each one for soldering issues cold solder joints etc... I found one solder joint that looked like it did not have enough solder and so I added some to it. I then cleaned the boards off with canned air and reassembled and reinstalled. And it appears to have fixed all my spindle issues. So no more dipping and no more shutting off.

I ran the spindle at 500 RPM 2000 RPM and 6500 RPM for some time with no issues (knock wood) so at least for now the machine is working.

I plan to cut another test part this weekend and then try and make my first real part a telescope pier adapter soon here is what that will look like. I have two pieces of stock a 10 x 10 x 1 piece and a 10 x 10 x 2 piece both 6061 T6 that I will cut this out of.



It's only taken me three years to get here whish me luck

[slowtwitch]

My spindle is still running after my re-flow of the main board. Good luck with yours

[SWATH]

Any chance of posting a picture of the offending solder joint. I haven't even looked at my panel board.

[allenj20]

I should have taken a picture but I did not know at the time that it would fix anything. I am sort of hesitant to even touch it now that it is working. If I have it back apart I will take a picture.

[chipmiser]

I should have taken a picture but I did not know at the time that it would fix anything. I am sort of hesitant to even touch it now that it is working. If I have it back apart I will take a picture.

Hi all,

I wanted to give an update and some hope on the spindle problem. I played the voltage, power, ground game for about 5 months, then finally got a replacement controller board mailed to me and guess what,,,the drop I was seeing below 1000 rpm went away!
On the down side, my RPM feedback on the controll panel is inop, and I have seen some dips at high rpm, but I am in a lot better situation now than with the rpm drops I was having at low rpm.
An AC motor with VFD drive would sure be nice, other than that we will have to ask for board swaps until finding one that works.

[SWATH]

Good luck with that, Mikini does not acknowledge that their board has any problems. I experienced similar things. No matter what I did on my end it did not help, but a new board solved the rpm dips but now it will not get passed 3300rpm and the rpm does not track correctly. I had a program that had an s500, and the panel read that it was spinning at s687.