Luthier CNC

[MikeyC38]

Hi blueskin
Looks a treat and a nice build. It is worth investing in specialised shim stock, because it allows you to shim precisely. see here
Also get you axis nomenclature clear. If you assume that the bottom left corner of your machine (looking top view) is 0,0 then the Y axis is the axis between the gantry sides and the X axis is the longest axis. Z zero is the topmost point of travel on the z axis.

Now start to work out where cable chain will run. This is something I did'nt do until I was at the same stage as yourself. I had to lash something up but luckily the design had space for aluminium channel to be fitted to support the chains

Finally for your spindle mounting, also try and design some means of adjusting for tramming the spindle. It will make your life easier. At the moment I'm using shims and it is tedious!

Keep going!

Michael

[Voicecoil]

Also get you axis nomenclature clear. If you assume that the bottom left corner of your machine (looking top view) is 0,0 then the Y axis is the axis between the gantry sides and the X axis is the longest axis. Z zero is the topmost point of travel on the z axis.l

Surely if you're standing at the front of the machine looking down, (i.e. 0,0 is front LH corner) then this is the opposite to how you'd have X and Y on a normal graph?? I'm with Bluesking on this one :-) Not that it really matters, he's made it perfectly clear what he's doing.

[cropwell]

Most 2D/2.5D drawing packages use the normal mathematical convention that the X axis is L -> R as you look at the paper, the Y axis is at right angles to it. How you orient your paper or machine is irrelevant. My machine is in portrait mode and it just makes it easier to visualise if it is the same as the drawing. My Z zero is at the top of the workpiece, but my Z homes to the top of travel. X and Y homes to Left and Nearest me respectively. I just find it less confusing this way and therefore mistakes are less easily made.

[MikeyC38]

Hi Guys

Sorry everyone, this is what I meant - standard landscape graph mode.But I of course it does'nt matter which way you do it providing you know what to expect...

[bluesking]

Wow, what a controversial issue my axis labelling has turned out to be! I'm happy with my system, long axis Y, short axis X, corresponding to a portrait graph as you guys call it.

[bluesking]

Z axis build today.

aligned the hiwin carriages first of all as I can't get to them after anything else is assmebled


then finalised the fit of the hiwin rails


then ballscrew aligned and attached the spindle once I was happy there was no binding


entire travel moves smoothly, it is easily pushed down by hand, not so much up for obvious reasons. My biggest concern here was that the Z axis would fall under its own weight. Well, I got lucky, there is just enough friction to keep the axis from falling down so I won't need to bother with a brake. Here is a video of how it behaves as it is - this is without the belts/servo connected, so after connection there will be even less chance of it falling after powering down:

https://streamable.com/z05b9

bolted on the reinforcement struts to the base to improve rigidity - seems to make a noticeable improvement


quick measure up of the drag chain - I'll cut some Ali Plate to support this - one end will be attached to the gantry, the other directly to the table - not pretty but I think it'll work just fine - I liked Wal's build that he had his chain under the table, but I have my reinforcement struts there and prefer rigidity over neatness!



finally, a quick test fit of the servos to see if there is enough pulley adjustment range (broadly planned that there should be throughout the build!) and to check whether the belts I have are of suitable length. I need to buy a slightly longer Z axis belt, you can see that the servo doesn't quite mount properly as is - I had to shorten the support extrusion for it during the build as I couldn't be arsed to cut an indent to go around the ballscrew bolts.