CNC Machine Setup and Alignment Part 3: Table Parallel to Motion

[@dylanw6393]

I think this is excellent advice. Hobby cnc machines are a great way to develop skills and learn a little maintenance diagnosis. I bought a used one. I'm glad I didn't buy it new though. Just got 3 fadals I'm very glad there's such informative resources as this channel. 👍👊

[@marson8870]

Thank you so much for this series. I’m making a diy cnc as a newbie and this is pure gold.

[@bikashtripathy9186]

So knowledgeable videos sir

[@jsincoherency]

What is the downside of surfacing the table to take the error out of it?

[@lsmullin62]

Not sure if your still checking this but we found that our y axis was .015 off. We have a 2006 boxway. Any ideas on how to go about figuring it out?

[@AtManUnlimitedMachining]

In what relation is it off by?

[@lsmullin62]

@@AtManUnlimitedMachining we did this test. When running the y we zeroed the indicator with the table all the way to the back of the machine. When the table was at the front of the machine we had dropped .015.

[@AtManUnlimitedMachining]

Wow, that is a lot. Given that much error it will be hard to figure out the root cause with just this one test. I would do some tests with a level and or laser to see if its angular error or if its a linear error in one of the planes.

[@lsmullin62]

@@AtManUnlimitedMachining I think we have it narowwed down to the turcite on the front x way. 😭

[@lsmullin62]

Y backlash appears good. .oo1 X looks good as well. Found a guy here that knows his stuff (fadal service guy) and he is helping out too

[@tomaszstaron1408]

Could I ask you to do 1 thing for me? I need a photo of table back side - where the carriages are. Also would be nice if you have some pic what is the distance between them - I'm building my DIY machine based on Fadal VMC15XT - according to the specs and manuals from internet but cant find this information.

[@AtManUnlimitedMachining]

Machine is running making parts, no way to take that photo or measurements at this point. I think I show the trucks under the table in some of the videos. But your measurements should be based on your machine and travel.

[@tomaszstaron1408]

The problem is I'm trying to fit to rails I already have, but always could buy another one if it should be 250mm longer - I have Rexroth 25C, 776mm and the table from conventional machine I did not use (FNC25 tilting table which is 600mm long). Almost everything other is to the spec with 15XT. Need the aspect ratio for how long the X rails are, and where the carriages are possitioned on the table, also how long the table is in 15XT. Could you just mesure the table? In my opinion they should be possitioned in 1/3 of table lenght (each side), so the rails should be 1/3 longer than the table to full usage of the table (spindle center should reach end of table). If it is on a 15XT manual, I'll find it... I have to model this in some CAD to check it... ;)

[@AtManUnlimitedMachining]

The rails are 1000mm long, the table is about 30 inches long on the VMC15. The XT is bigger. It's a little more complex to design a machine then bolting on some rails and trucks. By time your all said and done you can buy one of these machines in usable shape for less then $10K US.

[@tomaszstaron1408]

To design it is not a problem. The problem is than to do it and do it right ;)) Here in Poland its not so easy to buy this kind of machine for equivalent of 10k$. Most of them are from Germany, where working on heavy production cycles, some of them are totaly devastated. It could be a problem to buy a machine and then invest another 10k to repair it. For 3-5k$ you could build your own from scratch on Hivin/Rexroth parts if you only have some possibilities (for example doing the milling on large and heavy details like machine corps inhouse as I do). And its not my first machine been build. I have done some retrofits with manual machines to cnc, also build some 3d printers and few plasma cutters - designed and built almost on my own and as tight tolerances as in factory. Whatever - another thanks for all the information you supported me - as always it is huge value on my works (I've watched all series yesterday night). Very appreciate.

[@AtManUnlimitedMachining]

Fair enough, sounds like you did your homework. Let us know how you make out! Thanks!

[@sagarjadhav3815]

😮

[@WatchWesWork]

This isn't exactly right. You should not be grinding those shims unless you can verify that your linear guides are in perfect condition. Most likely you have wear in the linear guides. Removing and grinding the shims will just mask the problem more or less like milling the top of the table. The purpose of the shims was to correct the flatness of the table when the machine was originally built. The table was not perfectly flat, so they used the shims to pull it flat. You can't just grind them willy nilly.

[@AtManUnlimitedMachining]

Wes, I don't think I advocated "grinding willy nilly". You must take careful measurements and understand what to adjust to bring the machine in. Seeing how the linear slides are brand new and just replaced, I would call them "perfect condition"