[mcphill]

I had the same issues when I was running straight from the PP to the spindle, so the "offset" was not introduced by the SmoothStepper in my case. If it is truly off, there is likely a scaling factor somewhere in Mach that could be used to make it match better...

[SWATH]

https://www.youtube.com/watch?v=MniZ...e_gdata_player

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[SWATH]

I also fixed the issue with the commanded rpm in Mach not registering accurately on the front panel. I took a bunch voltage measurements of the PWM signal at various commanded rpms when commanded from both the Mikini front panel as well as Mach then compared them. I plotted a line graph and noticed the disparity was greatest at the lower speeds but pretty close at the high speeds though not perfect. It looked to me like the scaling was off on the low end by coincidentally 200rpm and the high end by about the same. The computer was assuming the that 200rpm was actually 0 as far as the duty cycle of the PWM was concerned whereas the Mikini front panel was scaling from 0 and assuming 0 rpm was 100% duty instead of 200 rpm (minimum allowed). I looked in the Spindle Pulleys section under Config in Mach and it was set to 200 minimum and 5000 maximum same as the front panel but this was incorrect.

To make the two align perfectly the min speed in Mach must be set to 0 and the max must be set to 5250. Now the commanded speed in Mach displays perfectly in the front panel.
Attachment 196800

Mike, we both were right, it was a voltage issue but one controlled by the settings in Mach.

[slowtwitch]

This is great stuff !!!! Keep the posts coming

[SWATH]

Sorry guys I fell of the map for awhile. I was wrapping up things at work before I left, trying to score an oscilloscope to diagnose some circuit problems and waiting on some professional help from a friend to advise on the circuit project. I don't have a lot of time to detail what I did right now, maybe tomorrow, but basically everything is working as it should. I'm still tying up a few lose ends on the VFD intergration but they are minor and will be sorted out soon. I mapped the RPM of the ac motor under manual mode control and Mach control. I don't know if I'm happy with the accuracy of the actual RPM vs the commanded RPM. Can someone tell me if this is normal, can be improved upon, or if it even matters than much in machining? It's about as good as I could get it with adjusting the gain and the offset.

[Susan673]

Can't wait to see the results with the AC motor attached

[SWATH]

Here are some pics of it mounted and the new and improved circuit:
Attachment 202146

Attachment 202148
Attachment 202150
Attachment 202156

Machine in it's new home:

[slowtwitch]

I want to see a video of this thing running and making chips

[SWATH]

I've been working on the motor mount and here is the top piece of a two piece design. I have video of machining it using the old motor but that will have to wait a bit for me to get it edited and uploaded. My machining videos seem to suck because all the coolant and splash obscures the view of anything, oh well maybe one day I'll get a go pro and put it inside the enclosure. Here are some pics though:

Attachment 203372
Attachment 203374
Attachment 203376

[SWATH]

Getting closer


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[hosamsoft]

i have c.b.ferrari s54e with control elexa e132 please cat you send me the catalog of the elctronic any one can help me i have problmes with the machine

[SWATH]

Btw I have discovered that the mill is seriously out of tram in the Y axis so I will have to deal with that and a heavier motor will make it worse. With no adjustments curtesy of Mikini I'm guessing I'll need to do something with the column. Any tips Pete? Did your tramming and bolt/washer replacement eliminate the play in the Z axis when pressing on it. Mine moves several thousandths just by gently pushing up or down on the spindle head or pulling or pushing the column.

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[allenj20]

Looks great man nice work on the mount. You are almost there keep going.

[SWATH]

Milled some holes for 1/4-20 socket head cap screws, transferred the holes to the spindle head, drilled and tapped them, and set to motor on top to see what it looks like. Next I need to figure out how I'm going to open up the bore on the pulley and put in on the rotor shaft.


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[SWATH]

I ordered a tram gauge but am holding off of ordering shim stock until I see what I'm dealing with after the gauge gets here. I think it is almost dead on in the X but the Y is pretty far off I can tell.

Here are a few minor upgrades I did while machining the motor mount. I kept losing coolant flow from chip clogging so I came up with something that works perfect. A flower basket from Lowes and a seive from Kroger (on sale for 4 bucks).

Also a length of 3/8 id vinyl tubing from Lowes for washing all the chips down on the inside of the enclosure.




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[slowtwitch]

Swath, It's great to see you making headway with this project As for the tramming thing, I haven't tested the movement of the column since I installed the new bolts and washers and trammed it. I had a bunch of orders to fill and went right to work as soon as the mill was ready. I'll setup the dial test tonight and see what kind of movement and measurements I'm getting. If time allows, I try to post a video of the mill using a 2.5 face mill and the cut results.

Since I'm here. I might as well give you and the folks on these forums an update on my VFD...AC motor replacement. The mill has been running flawlessly. It's an extreme pleasure to be able to turn on the machine, setup and cut without any thoughts of whether or not the spindle will fault. I have actually cut my machining times down more than half and I could probably go faster ..if I wasn't such a chicken

Since 99.9999% of my work is with aluminum, I'm constantly running the spindle at 6000 -6500 rpm. I would like to move up to 7200 rpm, but, I still have the original spindle bearings and they will get very warm.

I don't have a cut calculator such as G wizard and such ( I kind of go by the sound of the cut) but, I'm currently cutting full slots with a .375 carbide 2 flute rougher, a depth of.110 at 35 IPM. I could never do this with the old spindle without faulting and snapping an endmill.

There is a down side to this upgrade. CHIPS, CHIPS and more CHIPS. Since the mill is running like it should, you will be producing more chips than you ever had with the old spindle. I'm constantly having to clean out all the chips. Chips are everywhere ...I like it....it means the mill is working.....lolol.

[SWATH]

I have an insane idea. I might want to open up the pulley with my criterion boring head. I say insane because I have never been able to get a decent surface finish with it using the carbide inserts on steel. The pulley is some kind of steel and is currently about 0.866 and needs to press fit on the rotor shaft which is about 0.880 so I need to remove about 0.014, pretty slim margin for error. I need advice on what to do, feeds and speed wise, DOC wise, as well as what boring bar to choose. I have two carbide boring bars with different size inserts made for steel. I also have some C6 carbide boring bars that came with the Criterion although some of them are chipped from unsuccessful boring attempts. Because I've not had any success with these I'm also contemplating using one flute of a 1/2in. endmill for the high positive rake. What say you?


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[slowtwitch]

This brings back some memories I bored out a pulley for my lathe using one of these boring kits. I did it on my old round column mill. I didn't cut for an interference fit, as the pulley had a set screw. I used the brazed on bits and it worked pretty good

Also, you mentioned about how much movement I am getting on my column after tramming and using the heavy duty washers under the bolts. With some pressure, i can move the column about .0005".

Here's a video of the tramming results.....

Mikini Tram - YouTube

The face mill is 2" , with 4 Korloy SEHT1204 AFFN X83 carbide inserts for aluminum.

[SWATH]

Thanks for the video Pete! That tram is nice. When I face mill like that there a ridgewhere the two paths overlap about the thickness of a playing card.

I bored out the pulley to what I think will be an acceptable fit. It won't slide on the shaft but if I tap it with a rubber mallet it will just start to go on, heating should allow me to get it on there. I used the chipped endmill as a boring bar.

I also checked the tram and just as I expected the X was dead on but the Y was way off. Trammed from the factory with no need of adjustment my ass.

X axis (both indicators on 0)


Y axis (about 0.007 leaning forward)


I have some shim stock on the way. BTW I don't think my column bolts have washers at least I can't see them.

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[mcphill]

I have never measured my tram, but I have done 3 inch fly cuts and have no ridges. I am very happy with the lack of ridge as well as the surface finish. Maybe I got a "good one"? I don't plan to look at the tram or I might get in a spiral of ever-checking it!

I DO want to get to a VFD project, though, so please do continue to post your progress! I have been so busy at work that I don't get to play on the Mikini nearly as much as I would like. I have also been doing 3D jobs in wood lately, so the tolerances are pretty darn forgiving...