[FannBlade]

[Mikini] We do not condone the action of the poster due to the highly dangerous procedures and/or but not limited to the questionable outcome of varying the operating parameters outside of design specifications given that the origin of the "problems" the user claims to be experiencing are no doubt due to the unbalanced and unclean supply power as well as improper grounding that is common among ignorant residential users lacking appropriate accreditation from an institute specializing in isolating electrical anomalies specific to our industrial grade machines. We highly recommend in the strongest terms that no one attempt anything remotely close and/or otherwise similar to the detailed actions perpetrated by the user. Doing so will automatically cancel and void any remaining warranty or technical support privileges and may subject the unwise user to an inoperable or otherwise malfunctioning machine and serious injury or death of but not limited to the user and the user's family, pets, and/or neighbors. The AC modification of the spindle motor and driver is far inferior to the BLDC used in our industrial machines anyway so such actions are effectively taking a step backwards in technology and performance. (BTW Allen contact us, we would like to know how you did that, so cool)[/Mikini]

Just pullin' ya tit mate.

Perfect! (group)

[SWATH]

Crap... I guess I'll cancel my orders...

They didn't actually say that, it was a joke.(wedge) But I'm certain it would probably void your warranty.

[Sweeney]

They didn't actually say that, it was a joke.(wedge) But I'm certain it would probably void your warranty.

I know that! :cheers: I was joking as well. I already have plans to use the Mikini motor as a counter weight on the Z axis instead of the gas struts...

My Mik-Allen parts are en-route.

[howecnc]

Wow, tough crowd. I would still like to hear Mikni's opinions of this transformation though I guess they would have to be thick skinned and be prepared for a lynch mob.

[SWATH]

Wow, tough crowd. I would still like to hear Mikni's opinions of this transformation though I guess they would have to be thick skinned and be prepared for a lynch mob.

I would like to hear as well. If they came and said "Ok we goofed, everyone having spindle problems will receive a new controller and motor that has been extensively tested to work perfectly and it has plenty of low end torque to drill and mill hard steel and you'll get it within 3 weeks" I would start a website called Mikinimechisawesomebuyonenow.com, after I confirm it works of course.

If they came and said the usual stuff they say, I would expect dissatisfied customers to continue lashing out in exasperation.

[howecnc]

When can we see some drilling with this retro fit?

[allenj20]

Ask and you shall receive. Been busy with work the past week so have not had much time to mill till this weekend.

Here's a couple of videos

[ame=http://www.youtube.com/watch?v=tDFgQ-YkeeM]Mikini 1610L motor and VFD replacement project video 11 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=nM3bOxm6sDY]Mikini 1610L AC Motor and VFD replacement Project Video 12 - YouTube[/ame]

When can we see some drilling with this retro fit?

[allenj20]

Cool I am going to start on your motor mount this week. I just got the stock for it in last week. For power supply I was able to keep the Mikini power supply and DC power board. If they ever act wonky though I will ditch em. I would probably go with something like this to power the stepper drivers. The VFD just takes single phase 230V AC.

CNC4PC

I just ordered my motor, VFD and main board for my Mik-Allen project. I'll need to pick your brain, Allen, for the rest of the bits like power supply, etc.

I really appreciate the work you've put into this!

[mcphill]

GREAT clips Allen, thanks SO much for sharing. The spindle speed looked rock solid on that steel cut. Can you fill in a few blanks with that cut? What was the width of cut? Did you base the speeds and feeds off of GWizard, and if so what "conservative-aggressive" setting? Thanks again!

I really want to do this now... Just don't see when I will find the time... Can I fly you out to do mine?

[Sweeney]

Looks great, Allen. I got my motor, VFD and board in. I'm trying to get a car project out the door so I can dive whole heartedly into the mill.
I'll send you a PM with my email.

[allenj20]

Well the first pass was full width .500 and the second was something less. The feeds and speeds for that cut came from the NFS wizard in Mach 3 I was not sure on DOC the wizard makes no recommendation for that. So I went with .020 DOC. I was looking at GWizard this morning and it says 900ish RPM at 7 IPM .230 DOC

That's the most aggressive setting. I don't know about that, that seems nutty mcnutterson.

Hehe I got that Emco project up next you want to fly out and lend a hand I will return the favor

GREAT clips Allen, thanks SO much for sharing. The spindle speed looked rock solid on that steel cut. Can you fill in a few blanks with that cut? What was the width of cut? Did you base the speeds and feeds off of GWizard, and if so what "conservative-aggressive" setting? Thanks again!

I really want to do this now... Just don't see when I will find the time... Can I fly you out to do mine?

[Brian L]

RPM on the steel should/would conservatively be 1500 rpm, feedrate about 20 to 25ipm and depth of cut of at least .250 (half the diameter) at full width, if you do narrower width of cut, say .250 (half the cutter diameter) and climb cut, you could most likely get your depth of cut up to 1x the cutter diameter, so .500.

Also, on the drilling thru the aluminum, don't need to peck every .050, more like 1/4". Parabolic flutes on the drills do work, dunno that you or I will ever notice the difference of less than hundreds of parts though... They are considerably weaker too... so if I have ever snapped off drills in holes, it would be the parabolic ones....

[allenj20]

Hmm interesting, Sounds like I need to do the steel cut again. I will try it again and work up to that DOC I don't want to dive straight in to .250 DOC in steel I just got the darned thing working right. But I will go back and try some more aggressive cuts in steel.

RPM on the steel should/would conservatively be 1500 rpm, feedrate about 20 to 25ipm and depth of cut of at least .250 (half the diameter) at full width, if you do narrower width of cut, say .250 (half the cutter diameter) and climb cut, you could most likely get your depth of cut up to 1x the cutter diameter, so .500.

Also, on the drilling thru the aluminum, don't need to peck every .050, more like 1/4". Parabolic flutes on the drills do work, dunno that you or I will ever notice the difference of less than hundreds of parts though... They are considerably weaker too... so if I have ever snapped off drills in holes, it would be the parabolic ones....

[Brian L]

Well, agreed, you don't know what it will do on a regular basis yet, but I'd start at .1 deep, then increase by .1 each time and see what it acts like. Remember, climb cutting with about 1/3 to 1/2 the width of cut of the endmill diameter is going to be the sweet spot, so in a facing operation, best to start on an edge and do decreasing passes towards center in a clockwise circle around the part.

[SWATH]

RPM on the steel should/would conservatively be 1500 rpm, feedrate about 20 to 25ipm and depth of cut of at least .250 (half the diameter) at full width, if you do narrower width of cut, say .250 (half the cutter diameter) and climb cut, you could most likely get your depth of cut up to 1x the cutter diameter, so .500.

Also, on the drilling thru the aluminum, don't need to peck every .050, more like 1/4". Parabolic flutes on the drills do work, dunno that you or I will ever notice the difference of less than hundreds of parts though... They are considerably weaker too... so if I have ever snapped off drills in holes, it would be the parabolic ones....

Good info Brian thanks. What would recommend for a .180 drill in 4140HT 1.25 deep? I was using a regular carbide drill but never really got the peck cycle that worked good, it would either take all day to drill a 1.25 deep hole because I had to peck every .025 or something or else the drill would completely wrap with stringers then jam the drill in the hole, until it eventually snapped in a hole trying a .25 peck. So I ordered a parabolic cobalt drill to try. Do you use full retract or just a breakchip peck? Same goes for my 14mm drill I have to use a tiny peck or the chip wraps up the drill and stalls the spindle.

[Brian L]

OK, it's a pretty general statement of 4140HT, heat treated to what? Rc 28-32, 35-43, or harder? Big difference in the machinability. I would start on the .180 diameter drill with 1000 rpm, 5ipm feedrate and peck with no less than 1 diameter, so .180 for the minimum peck. Unfortunately G83 is going to give you peck length that isn't variable, I can't remember what code it was, but on the lathes, you could get a variable depth peck, say your first peck was .5, then the next might be 75% of that, then 75% of the last one and so on until it hits the .180 minimum peck amount.... kind of handy on deeper holes.

I wouldn't use carbide on that deep of a hole unless you have your machine all squared away, a dip in rpm and you are toast. Parabolic Guhring or OSG would be the way to go, and their websites will give you better, more specific numbers for feeds and speeds.

As for peck vs. woodpecker (G83 vs G73), I'd retract, gives a chance for some coolant to get into the hole. Remember, if the long stringy chips are coming up and out of the hole, and spinning around, then they are out of the hole, and that's the key issue, having a bird's nest wrapped around the drill when it's done is a mess, and in inconvenience, but it means the chips aren't packing into the holes.

Regarding the 14mm drill and chips stalling the spindle? I don't think it has to do with the chips... it has more to do with the gutless spindle.

[allenj20]

A couple of more video updates hogging steel

[ame=http://www.youtube.com/watch?v=_MSIvguQdNk]Mikin 1610L AC Motor and VFD Replacement Project Video 13 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=GbD0YOIzPaY]Mikini 1610L AC Motor and VFD Replacement Project Video 14 - YouTube[/ame]

[Sweeney]

Well, we now know your spindle has the ability to rattle the rest of the machine apart
Good show, Allen!
Does anybody need an unused Mikini main board and/or motor? I won't be needing mine. The Mikini motor isn't heavy enough to use as my counter weight for the Mik-Allen conversion.

[Brian L]

Allen,

Very cool, and yes, you are finding the limits of the rigidity of the machine. I would throw out there that you are still spinning a bit too slow, 1/2" carbide in steel should start at about 1500 rpm, that will smooth out the vibration considerably. Also, write the programs so that you keep the width of cut around .250"... as you noticed in the second pass of the second video, the narrower pass was much quieter and more stable.

If nothing else, you have learned how to clean off the machine.... make a deep cut and everything vibrates off to the floor! :-)

Seriously, fantastic job on the motor conversion, it will not be the weak link in the machine any longer. Not only should all the guys in the group thank you, but Mikini owes you a big apology and thank you for doing all the prototype work to put a real spindle drive into this thing.

[mcphill]

A couple of more video updates hogging steel

Mikin 1610L AC Motor and VFD Replacement Project Video 13 - YouTube

Mikini 1610L AC Motor and VFD Replacement Project Video 14 - YouTube

Thanks once again. Case closed, Mikini's spindle has NO guts... Not sure those were the "best" way to cut steel, but you sure weren't even CLOSE to stalling out.