Next is the Z axis motor arrangement.!! Why have you got the motor fastened to the front plate and sticking out the front.?
It looks to me like you have enough length to the Y axis front plate to mount ball-screw on this and fasten motor other way round. Your rails look shorter than the movement range your ball-screw will allow.
If so and it's longer than your Y axis front plate then just do away with the bottom bearing and shorten screw provided it gives enough screw range to use all rail length. On a short Z axis screw you can easily get away with this and it also makes aligning screw/nut that bit easier.!!
Other way is to have longer Y axis front plate and do it this way, both work.!! . . . Either way Your better off with screw and motor has I've described because it will allow higher acceleration from the Z axis which helps if your planning on 2.5/3D work.!!. . . .No point making the motor/drive work harder than needed.!!
Rest looks ok except that I'm not too keen on the low base frame due to large adjustable bed range.!!. . . .Do you really need that much adjustable range because it's compromising the strength quite a bit.?
Last edited by JAZZCNC; 28-08-2013 at 02:46 PM.
Y-axis rear plate...partly to help keep crap out of the leadscrew etc Thought it would add some extra sideways/diagonal rigidity...can easily drop it.
Z motor - probably didn't think it through quite correctly...with that arrangement, the y axis front plate is considerable shorter than it would need to be to have the leadscrew & motor attached.
The rail lengths are pretty much spot on compared to the screw length - maybe i've got the Z axis linear bearings spaced further apart than needed? (170mm outer face to outer face along the axis). I'll look at swapping the leadscrew & motor to the Y front plate.
Base frame - do you mean raise the lower shelf/surface, or reduce the overall height?
I don't really want to lose much overall height if possible as it will be at a good height for me to work with it at...rather than being low down on the floor like my last mdf machine which was a major pain in the back.
I don't necessarily need all that adjustment - I could raise the lower surface & add more cross bracing to the outer frame?
RM1605 nuts are approx 50mm in length so for 180mm travel then 250mm thread length is plenty.!
Yep - sorry, I had another look at the Z-axis screw....I did shorten it earlier - but it looks like I lost that set of changes & didn't think/notice when I was copying the sizes down above.
Have started revising the layout - its fitting together nicer with the z-axis sorted the right way round :-p
I'll do some more tweaking tomorrow - should have a fully revised version then
I've been fiddling with it again
Beefed up the diagonal cross bracing on the main frame - all diagonal cross braces are now welded at one end & bolted at the other.
Also rasied the lower surface/shelf - removed the very bottom height adjustment position so it could come up a little further.
I've done a fair amount of tweaking to the gantry & z-axis.
The knock on effect of extending the y-axis front plate to mount the Z motor meant that the z-axis wasn't giving me an optimal range of movement. I had to shorten the height of the gantry (between y rail mounting surfaces) from 200mm to 175mm in order to sort it out - everything is now peachy with a good range of movement & 2mm+ clearances all round.
Making these tweaks along with removing the rear panel looks to have saved a decent amount of weight from the gantry as a whole
Am I safe to start peppering the parts with holes & adding pinions etc ?
Edit: Just spotted that the Z rails could now be longer than needed as well...or the bearings might need moving lower.
Last edited by CraftyGeek; 29-08-2013 at 11:58 AM.
Personally with you just starting to weld I would urge you to chamfer the two parts to create a 'V'.
Welding can be a tedious venture and without, lots of practise it can take some time to master. So I would not have a gap as you mentioned in image two (I think) as filling gaps with weld is another learning process.
As I understand you are not too far from me. If you like, I could come and give you some welding tips / help over the weekend.
BUILD LOG: First steel diy CNC router buildBy ivars211 in forum DIY Router Build LogsReplies: 59Last Post: 28-07-2014, 07:29 PM
By mart154 in forum DIY Router Build LogsReplies: 27Last Post: 19-09-2013, 04:48 PM
By Greeny in forum DIY Router Build LogsReplies: 8Last Post: 19-08-2013, 07:26 PM
BUILD LOG: 7' X 4' Steel frame buildBy Ricardoco in forum DIY Router Build LogsReplies: 6Last Post: 28-10-2012, 05:02 PM
By MikeyC38 in forum Gantry/Router Machines & BuildingReplies: 12Last Post: 21-10-2011, 03:50 PM