planing on placing the order for extrusion today
So I've decided to start building my own CNC. I have an Openbuilds OX, but want something a little larger and more precise\rigid. I aim for a work area of approx Y900mm and X1000mm. I choose wider on the X because of easier placement. It will be used mostly for Wood, but also some aluminum cutting, engraving and vcarving.
I have not decided on all the parts but have some thoughts.
The base frame I plan to construct with steel and level the top with epoxy, I have a friend with a flat table we can lay out the frame on and weld.
For the CNC i will use Misumi Alu extrusions
for the gantry X-axis i will use their GFS8 100x200 High Rigidity type
for the Y-axis i will use HFS8 90x180
for the reminder of the base HFS8 90x90
for Z-Axis i will use a 12" Parker 404XR Linear actuator
Spindle: 1.5kw air cooled spindle ( allready have this, but might change it at a latter point)
XY Motors: steppers or Teknic ClearPath servos. I plan to mount them direct to ball screws
Linear Guide Rail: HIWIN HGR25, 2 for X and 4 for Y
Ball Screws: 2505 TBI\GTEN C5 Rolled
Side plates I plan on having them cut out of 20mm aluminium
So the big question, any big design faults here or any alterations i should do before i order the alu extrusions?
Here is my first scetch of the aluminum Construction
John
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Last edited by jajohnsen; 01-18-2017 at 05:59 AM.
planing on placing the order for extrusion today
Last edited by jajohnsen; 01-19-2017 at 07:18 AM.
So next on my shopping list is linear rails.
I plan on using HIWIN HGR25 with HGH Blocks
4x 1100mm for Y axis with 8 HGH blocks
2x 1290mm for X axis with 4 HGH blocks
What would you recommend for the following.
Precision: C or H
Pre-Load_ Z0 or ZA
Dust protection: SW or SWZ both are high dust protection but the SWZ also has a scraper in front
Hi. What a similiarity with my build
Absolutely, your thread was a great inspiration. Hope it's ok that i borrow from it
For the steel base i will look at 1jumper10's 2nd build for a friend.
here is a updated view with rails
Last edited by jajohnsen; 01-19-2017 at 04:34 PM.
Hi Jajohnsen - That is going to be a nice machine. Misumi extrusion is very high quality. Regarding the Y axis linear bearings, you probably don't need the twin rails on each side. If you feel you needed the extra load capacity I would go with 3 bearing blocks on one rail instead of a second, parallel rail.
Thanks 1Jumper10, i guess the second rail in the y axis was there just to be safe, as I'm not good at calculating load capacity. You're probably right that one rail is enough so I'll update design for that. it's should be easy to add more later if i need to.
No problem here. I have never thought my build can possibly inspire someoneAbsolutely, your thread was a great inspiration. Hope it's ok that i borrow from it
Any particular reasons for placing Y rails to extrusion sides instead of placing them on the top?
I was wery unsure if i should place them on top or sides. Tried to find any pros and cons but havent found to much. I decided on the side as it keeps them a little farther away from dust\debris from the cutting, and i think the design of the gantry side plates will be simpler beeing only one plate connecting the gantry and guides and not two.
I have gone through the same thought process - rails on top or sides. Of all the reasons for or against one or the other, since the bearings are plenty strong enough to be mounted in any orientation I find myself returning to putting them in the best position to keep them clean. Over the side mounting does a decent job at this. Rails on top and even with the cutting bed is the worst. My first router was that way - lesson learned. The second router I built utilizes over the side mounting and they are staying clean. Another method would be top mounting the rails and raising them above the cutting bed; i.e. no risers, the gantry is mounted directly to the top of the bearing blocks. A lot of the machines on the UK CNC forum are built this way. There are some advantages that gain rigidity with this approach. Either way is fine. Which way is easiest for you might be the main consideration.
Yes for me i think the easiest way is on the side
Since you mentioned cleanliness,
I'm trying to decide which type i should select for the blocks on the linear guides. I see Hiwin have zw for the highest dustprotection, but not sure if i can get a hold of this. Alternative is ZZ or KK are they sufficient enough or should i get the ones with the highest possible protection. What do others use?
I think mine were just the standard wipers. These were OK but I did install some covers to keep debris off the rails just for a little extra protection.
Just a short update,
I'm currently waiting for the Alu extrusions and should have them within a month or two (ordered from the U.S. and for delivery by sea to Norway).
I also just ordered the HIWIN rails. HGR25 rails with precision H and Preload ZA for the carriages and decided to go for the ZWX dust protection. I'll have them in a couple of weeks.
Finally the alu profiles is here, now I'll start on the steel frame and design side plates for the gantry and mounts for the ballscrews
Well finally gotten some more work done, the base frame is welded and leveled with epoxy and mounted the aluprofiles.
I'm getting ready to order some ballscrews. I'm thinking to go with TBI 2505 grade C5 rolled, but I'm not sure what type of ball nut to go with and what preload if any.
I'm looking at either SFU or DFU type.
what should be my best choice bor the least amount of backlash?
any help greatly appreciated-.9
Newbie here but will the 05 ballscrew give you the speeds you are looking for?
good question,
I'm not sure, I've decided to use Clearpath Servos but don't know which ones yet. I've but in a mail to Teknic for help on that. When I now which servos to choose i can find out of it will give me the speeds i want.
What would be a good target speed? my working area is approx 90x100cm (35x40Inch)
Ahh, going mad here. to many choices and I don't know what to choose. and finfind al the formulas on the net for calculation just confuses me more
Maybe a 10mm pitch (or maybe 20mm) is better choice than 5mm and with the clear path servos i can choose the enhanced version which has 6800 steps per revolution, so resolution shouldn't be a problem i think. but how much torque do I need on the motors and would it be better going to 20mm ball screw if i go to 10 or 20mm pitch as i can use slower rpm for the servos?
and for the ball nut any recommendation for single or double configuration?