New Build 1000x600x200mm (newbie)

[Noplace]

I forgot to mention that I'm planning on using 2.2kw Chinese spindle and won't be changing that in the future for this machine, the bracket for that is 150mm I think, so should I reduce the Z plates width to 150 or stick to 200?

[routercnc]

In terms of width of Y axis plate then 200mm is reasonable to reduce racking of the Y/Z axis assembly as this spreads the Y bearings apart a bit. Some people make the plate have 'ears' where the Y bearings mount which can help with clearance and assembly. Not mandatory as it depends on the other details of the design, but worth a look.

I went with less than 200mm spacing to get more working space as it is primarily a wood cutting machine. There is no problem with mounting a 150mm wide plate to this to hold the spindle. You can use the real estate at the sides to mount DTIs, laser pointer, dust shoe etc.

In terms of height of the Y axis plate only needs to be as high as the Z ballscrew, fixed and floating bearing, and stepper connection dictates. You need to draw these to see how tall it has to be to give the required travel on the Z ballscrew nut. In practise this could be close to 240mm but there is no specific requirement to match the moving Z axis plate in height.

Bearing sizes - I used 15mm on the Z (but wish I'd used 20mm as they are much stiffer), 20mm on the Y (which I'm happy with) and 16mm SUPPORTED rail on the X (wood cutting machine). If I was to use profile Hiwin style rail then I would use 20mm as a minimum.

The way you have mounted the gantry to the X bearings looks poor, as seen in the front view picture. A very long cantilever plate which is OK for wood, but not ideal for aluminium. You should redesign this, or add a further connection up to the gantry, or raise the X axis to meet the gantry directly.

[njhussey]

Just have the sides going straight down like Jazz showed in his last post, you're making it uneccessarily complicated. To make the gantry really stiff ideally you'd drop it so it sits on the plate the X axis carriages...

(Clive beat me to it...)

[njhussey]

As Clive says you only need 2 or 3 mm, I've got about 3mm left for my Z stepper out of the 20mm plate...there's no real force acting on it so it doesn't need to be super strong.

[Noplace]

Thanks I think I got it now, here's one of em with 5mm thickness for motor:

[njhussey]

Spot on....

[Robin Hewitt]

I have never found a pulley separation calculator that got it right. I draw the two PCD's at around the separation I want, add two tangents to connect them as the belt would, trim the circles to those tangents, list the two arcs and one tangent then tally their lengths. Undo until I am back at two circles, tweak the separation and start again until I get it near as makes no difference. If you mount motor and shaft bearing in the same piece of metal you don't actually need any adjustment if your machine is accurate.

Make sure none of the pulley bolts coincide with the belt and if you are really canny you add a fixing for the plastic conduit that protects the motor leads, because that is never in quite the right place if you forget it now

[Noplace]

Hey guys, so just encountered an issue which is upsetting but hopefully with your guidance I can fix it. I didn't get a chance to take photos of the machine to show the problem but I'll explain it first now and hopefully post photos later if needed.

so I connected the actual side plates to the X Axis rail and ballscrews:


if you notice bottom 4 M5 screw holes are for connecting to the ballscrew nut bracket, this is the same screw you saw in the video, what happens is there is a mismatch between distance of the (4 M5 and 4 upper M8 holes) in the plate and the screw and rail distance so I have to lift the side plate a bit up to match the 4 M8 threaded holes and the when I screw everything fit the ballscrew is forced to strain upwards and causing me jittery movement if going slow along with noise and stalling at the far end side ( tested with drill just like video ) . it is opposite of result in video , very bad hopefully ill capture it but I don't want to repeat putting the sides haha.

so my question, can you just solve this by machining the side plate to have the same slot solution as we discussed for motor plate?
instead of 4 m5 holes ill have a slot of same radius but gives me little tolerance to adjust the height correctly?

hope this is clear, if not I will post a photo of the real thing but the place I have my stuff in has no Air conditioner so I have to plan a shower after it haha.

[njhussey]

You can slot holes so that you can have adjustment there's no problem there, of course it's better if they're spot on but once they're tightened up it won't really matter. I cocked up the dimensions on my Z back plate for the lower bearing plate for the Y axis and they're slightly slotted, it's still fine!!

[Clive S]

After you have put in the slots and you get it all true you could then drill another hole through and put some dowels in to hold it in position. ..Clive