“There are only a few mechanical parts that should ever need to be replaced on your PRO CNC machine. It can be helpful to have these on hand to avoid machine downtime in the event of a machine crash or other issue.”
But when you go to the order page it says this;
“The PRO CNC Machine Spare Parts Bundle contains mechanical components that may need to be replaced due to normal system wear or under other circumstances, such as a machine crash.”
And more specifically in a bullet;
" (3) NEMA 34 Drive Spindles for your machine’s rack and pinion drives. This is a wear component on the machine and should be replaced every 6-12 months of machine run time."
The truth is the drive spindles wear on a pretty regular basis. The bearings less so but they do wear out as well.
AvidCNC needs to make that more clear for the new folks. They also need to describe the process to check the bearings and how to replace them while replacing the drive spindle.
We have some updates to that product (and those pages) that will be coming in a month or two. Stay tuned for that. We’re solving for more than just the verbiage
Since many of us are hobby users it would be good to state wear and repair expectations in terms of machine run time and not calendar time. To that end it would also be nice if there were some way of automatically recording machine run time. Maybe a Mach4 script or something in the spindle VFD code?
That’s a lot harder problem to solve than you might think… Picture two of the same machines running the same amount of time… One is running foam cuts and the other is cutting aluminum all day… Even at the same run time these machines are going to have vastly different maintenance schedules.
What we like to do is give people ways of determining what’s wrong, and how to replace those consumable parts: X and Y Axes - Troubleshooting
The reality is that pinions are probably the only somewhat common thing that people wear out. We pick the articles we put on there based on the stats of customer questions/warranty issues.
What’s been surprising to me coming from the “outside” and now being “on the inside” is that a lot of the stats around what breaks/what people complain about doesn’t line up with what you might think.
So then is the best indication of pinion wear an increased in backlash. All my previous experience has been with ball screw driven machines so I don’t have a good feel for rack and pinion.
That’s basically it. You can check with a dial indicator, even easier you can put your hand on the gantry near the bottom and the table and use your other hand to impart some force back and forth. If you feel any slop you know you should dig in further. The nice thing with our system is that the spring keeps the gear engaged with the rack so as things wear the gear stays well engaged with the rack.
In my previous custom setup I had nearly the same drive system, but there was no spring tension so a few tines a year I’d have to loosen my motors and pull them tight against the rack again.
Not to be obtuse, but that’s like asking for the wear and repair expectations of a kitchen knife. Depends on frequency and type of operation. When the knife dulls, it needs to be sharpened/replaced. When pinion gears wear, you need to replace them.
Generally, people know how to judge if their kitchen knife is worn. That is an extreme oversimplification and not helpful. Judging when maintenance needs to be done on a CNC is significantly more complicated. Not impossible to learn, just way more involved than “is it sharp?” Define pinion gear wear? How much is too much? How do you determine if it is worn to begin with? People who buy these machines aren’t always experts in how mechanical systems work. Some don’t care to become an expert. Maybe they just want a simple way to know if they need to swap out a part or do some preventative maintenance. Maybe you can’t tell people exactly how long it will take to wear out a pinion but you can give them the knowledge of how to determine if it is worn out.
I think the answer is a range, and it really depends on what you’re doing. A couple of examples:
I used to cut a lot of hard black plastic in my shop. Some customers didn’t care about edge quality, some wanted it as good as I could get it. Wear in the pinions drops the edge quality on the cut. For some customers that would warrant me replacing the pinions sooner rather than later.
Said another way: In my example the desired outcome would actually dictate if my pinions (or other consumables) were worn.
As far as I know there’s not a “spec” per se, but you can come up with your own pretty easily. If you have dial indicators you can power up your machine, set the indicator on the back of the gantry and push and pull it back and forth to see the slop. There will always be some on any mechanical connection. If the cut quality you currently have is good, the reading you have you can consider good. Note it down and check it a few times a year.
When I was running my machines hard (before I was here doing product for Avid) I made that a routine I’d do a few times a year so I could catch wear before it was a problem.
If/when your cut quality falls off you can go double check this spec (along with all of the other stuff you should consider when seeing declining cut quality like material quality, bit life, hold down, weather, etc)
You guys should do a write up with pictures or a video of this process for those who have little to no experience using indicators or measuring backlash.
You can get the total hours in the machine.ini file. Would be nice if there was a seperate one for maint cycles, but you can always reset this one if you want to track maint hours.
Hey man, I hope you folks are doing ok. As far as the screen I am running your JN woodworking branded screens on both machines. I’d like to see total machine hrs anywhere you can place it in the main screen or if it has to be in a tab screen then the file ops tab would be my choice. I trust your judgement if you find a better place to display. Then we can work on making a resettable one for total hrs this month, etc lol
