I dropped off for a little while but getting back in the shop. Gotta love the military. Pretty much picking up where I left off. Im now just waiting on the nuc5 to come in and get back to the software side…
Hello Dr.D-Flo,
I am attempting to control the PM-833VT VFD with the 7i76e, are there any references as convenient as your other wiring guides that you know of?
Would you mind sharing your spindle timing belt pulley CAD file? I am going to have to reconfigure my encoder for the new drawbar and this may save me some time and headache.
Here is the fusion 360 link: https://a360.co/33aEyzg
I have an extra printed one if you want me to ship it to you. You were incredibly helpful in making that video, and it would be awesome to pay it forward.
Thanks. I appreciate that but I can print it here. Just now getting my ultimaker up and running. It looked like you had the dimensions of the spline real close.
Todd Candee
Todd@thecandees.com
Yes that is because I printed it with SLS. Much better tolerances.
I’m actually printing nylon at very close tolerances now. Took some testing to get the shrinkage right but I printed the entire encoder mount including the timing belt pulleys within .05mm. scaled the parts to 1.01 to account for shrinkage. Bearings mount perfectly and timing belts fit nice. hoping to continue with this accuracy.
In my PDB conversion from TTS to R8 I decided to address my encoder mounting issues since I am going to have to move it. I wanted to address the “round belt” issue that I received criticism for but never had a problem with and the axial strain that the belt was putting on the encoder bearings.
I did my lathe first just because I was waiting for some parts for the mill.
The mill encoder mount is printing now.
Thanks David for the pulley file but I didn’t end up using it. I decided to mount mine a different way that would utilize some existing parts.
Attached are som pictures of the lathe encoder mount.
Looking at converting my PM833T mill to CNC and like the overall approach that you have taken. I’m interested in using servo drives and motors. I was taking a look at your Servo Drives diagram on your Manual to CNC Mill Conversion page Manual Benchtop Mill to CNC Conversion
I noticed that the mains power wiring for the control logic input power is shown incorrectly. Your diagram shows mains power going to the T3 terminal block which is for the regen resistor connections. According to the DYN4 Instruction Manual mains power goes to L1 and L2 on the T4 terminal block.
I’m guessing most would double check (and they’d be wise to) manufacturer data before making any connections. But, just in case.
I am almost complete with my R8 PDB conversion from TTS on my Pm-833MV. I ran the first part with the R8 ER20 holders I purchased and was able to run a 3/8 carbide flat endmill at .112" stepover and .505" depth in 6061 aluminum at 65 IPS in a Volumill pattern. This was not possible above 30 IPS with the TTS system. Very nice to chew through aluminum finally. Still have some kinks to work out on the PDB but it functions pretty well. The encoder mount is working well too. I am having to reprint it however due to an error in measurements. Still worked but the belt was out of alignment. I have the parts an tools on the way for a manual spindle lock. I will have to engage and disengage it at every tool change and there will be a saftey lockout while it is engaged. Still working out the code to make this happen.
To be honest I don’t think it needs the lock. seems to work just fine without it.
Dr Dflo,
Wanting to see if you withhold be interested in configuring a nuc for the original setup in the walkthrough? Minus the probe and tool setter.
Hey sorry for the late reply! This has been a super busy season for me with an upcoming wedding and finishing up my PhD. Did you get your software sorted out?
No worries! Appreciate you getting back with me. No I have not I need to get back on it. I got wrapped up with some military stuff and then when I got back from that. Ended up buying an airplane and then fixing that so it’s been busy here as well! my machine is complete it’s just the software side of the house . I’m gonna have to start fresh because I ended up buying the same exact nuc that you had listed in your walk-through.
I am running linuxcnc on a nuc5. what usb wifi dongle did you get to work with linuxcnc?
My nuc has an integrated wifi chip. I have actually not had much problems with jitter when having the onboard wifi on.
Hey, do you know what the ballscrew pitch is for x,y,and z in the heavy metal 833 conversion kit? Went to their site to research but it hasn’t been up for a while. Or, if you have the distance per revolution you are using on your machine that would be a big help. Thanks
i don’t know about those kits but most milling applications i have used and seen are a 5mm pitch. i don’t think you will have an issue in this range. you get into 10mm pitches on wood working applications.
the higher the pitch the faster the rapid rates you can develop but you trade off on power developed. so a higher pitch screw is going to require a bigger motor. so it boils down to what your target needs are? But a 5mm pitch would be a good starting point in my opinion for milling. you should be able to get more than enough of a rate of travel on a 5mm pitch. i would probably go with a 20mm diameter as well.
rapid rates have a few factors to consider. the type of motors are one. stepper’s vs servo’s? servo’s usually operate at a higher RPM. length of the ball screw can factor in if the length gets to long and then you run into things like screw whip. on a machine like this i don’t think it would to much of an issue since the travels are not that huge. the big thing is gib’s vs an actually linear way. the gibs are not as efficient and tend to bind as spots wear into them over time in the main work space.
They’re 5mm pitch. 20mm diameter
Hello Todd,
I am almost done converting my PM-833TV to CNC. I plan to post a bunch of images shortly. I think I remember you posting something about an oil seal at some point with respect to spindle heat. I too find that my spindle runs very hot. You can almost burn your fingers if you grab the spindle too quickly after it has been running. PM suggested loosening a retaining ring which I did, but it did not accomplish anything.
The OEM oils seal is 45 x 72 x 10. I think you suggested increasing it to 47 x 72 x 10.
I am totally new to this and have two questions. 1. How difficult is it to remove the existing oil seal. 2. You mentioned looking at https://www.avxseals.com for a larger seal. Can you help me identify the correct seal as they appear to have many different styles of seals.
Thanks again… Richard
I do run the 47mm but, just the other day I pulled my spindle to tighten it and when I fired it back up it got hot. I thought I may have tightened it too much. It turned out that if the seal is seated too deep it rubs on the bearing. Try backing it out slightly.
The only way I have been able to get them out is to destroy it. It is in really tight. I drive a flat screwdriver around the outside and pry it out. I’m sure there is a better way but I just keep a spare around. There are many oil seal removal tools you could try.
Todd Candee
Todd@thecandees.com