I help support the Nomad in our public technology library; done so for the past eight years. Currently the library is using a Nomad 3. I am looking for insight on two recent observations:
A brass colored ring, surrounding the bitsetter, appears to move upward over time. I had not noticed this before and have pressed it down several times until it is again level with the aluminum floor of the Nomad. Is there some cleaning or maintenance that should be done to prevent this or is this a normal occurrence during the ongoing use of the Nomad?
When milling small features, where the Z axis has minimal motion over the course of 30 or 60 minutes, the Z axis will struggle to raise-up for a bit change. It âchugsâ and eventually gives up and moves in the -X direction, sometimes dangerously low over the material. I donât produce a lot of dust but I am using a 1/32 or a 0.015" end mill. If I am attentive I can anticipate this failure and physically âhelp liftâ the spindle through this struggle to raise-up. I thought it might be sawdust trapped or compressed in the Z lead screw and have tried lightly coating the Z lead screw. That actually made it worse - I am thinking because the oil may have âcapturedâ more saw dust? I have since initiated much more rigorous cleaning - even in our public-use environment (cleaning levels vary between public users). I use a dedicated toothbrush on all lead screws as well as canned air to blow out areas difficult to reach behind the spindle. I do not observe this problem on the X or Y axis. I can re-initialize the Nomad and that generally brings the spindle, on the Z axis, up to its homing locationâŚeven after it has failed to raise-up for the bit change. Is there something I am missing or should attend to differently to minimize this problem?
While I teach Carbide Create and the use of the Nomad to library patrons I am self taught and know there are critical holes in my experience and I wonder if I am missing some basic maintenance related to these two observations.
I love the Nomad; it is an incredible, precise, and resilient machine (and the software just keeps getting better). Appreciate any insights on these two observations.
Re 2) This is almost certainly because the Z rails/bearings need maintenance and less
likely to be the leadscrew itself. I found that after disconnecting the AB nut the Z carriage
didnât slide smoothly; it should be drop under its own weight, even without the spindle
and motor attached but it didnât. I spent a lot of time flushing through with the correct lube
until it ran completely freely and the problem of Z not retracting went away.
I have excellent dust collection so I donât know what puts it into this state.
Thank you. I will do some cleaning and see if I can resolve this. Like you I donât know what put it in this state - it had worked well, without exhibiting this problem, for some time - but it is difficult to work around with a steady stream of new CNC users in the library.
With adequate support (so the cars donât fall off the rails) remove the spindle, motor and Z plate. Then service each car by flushing with vactra (messy and smelly) until it runs freely.
I donât know if there is a tramming procedure for reattaching the Z plate but it went back together accurate enough for my needs.
I am really careful about dust and swarf collection so I donât know why these got sticky so quickly⌠I am only a hobbyist and my run times are low but I can still see myself having to do this quite often to maintain quality.
I have removed the spindle and motor on the Nomad before without difficulty. I am going to tackle the Z plate removal this coming week and donât want to get âover my headâ in the process. When you reference âservice each carâ are those what run on the rails for the Z axis; what the Z plate attaches to? What happens if a car falls of a rail? What did you use for âadequate supportâ in your process? As you can tell, I am a bit nervous to do this, it sounds relatively straightforward, but I donât want to mess it up if I run into something unexpected. It sounds like your reassembly did not require any special tools to check alignmentâŚdid you just follow your reassembly with your regular projects and all worked well? Did you you Vactra 2, which, from posts in this forum and on-line is brown with a viscosity of 68?? Thanks for your response and your patience with me.
The âcarsâ should == âLinear blocksâ which are the metal parts on the rails which hold all the bearings.
If they come off the rails, then they will lose their bearings â repacking them is a pain, so donât let that happen. There are small plastic blocks which are the shape of the rails which can be used to remove them from the rails for maintenance, but that shouldnât be necessary, just put a small plastic clamp each end of the rails to keep them from rolling off.
Yes, we recommend Mobil Vactra No. 2:
for the linear rails/blocks on the Z-axis. For the round rails for X/Y use Super lube:
as noted, itâs available from some sewing specialty shops. I bought some from Amazon ages ago according to my purchase history:
I cleaned and lubricated the Z rails and my Nomad 3 spindle now lifts smoothly on the Z axis. Thanks @flynnjs and @WillAdams for your help, context, and additional community links.