Like that...but hopefully with better welding...
Last edited by njhussey; 23-07-2014 at 12:11 PM.Neil...
Or like this;
http://www.mycncuk.com/threads/6565-...2425#post52425Spelling mistakes are not intentional, I only seem to see them some time after I've posted
New photos of the progress
Yesterday i cut the steel and the aluminum pieces for the bed
I install a winch at the roof , as the weight of the table is big ( nearly 140 kgr so far) to handle with my hands
I turn the table upside down to full weld all the joints
I remove the middle piece as i change my plans. Another three pieces will be welded vertical to the sides of the machine
I put temporary the steel and aluminum pieces of the bed to get an idea how the machine will looklike
Solid works is very good but the real world even better.
I will use epoxy for the rails level but i try to be as precise as possible.
I chek the level of the table and the results are very good
I use two diagonal threads that they just touching each other ( that means the orners are at the same level)
Also i use a digital level that shows RELATIVE ANGLE between the diagonals 0.0o.
If you see the videoa the absolute angle is 2.0-2.1. That is not a real mesurement as the level fall from my wifes hands and has an offset 2.0o. That is not matter as what maters is the relative angle
Here are the videos
Last edited by ba99297; 24-07-2014 at 02:44 PM.The creative adult, is the child who survived
Coming along nice Vagelis. Don't waste too much time on trying to level just yet until your ready to do the epoxy leveling. Removing twist is important and it looks like you are doing a good job here.
I would put some more supports under the Bed. Even thou your using steel it will resonate if it's not supported in the middle. I would put 2 more pieces in there.
Also like as been said braces in corners to help keep square won't hurt.
Much nicer feeling building than designing isn't it. . .Lol
Thanks for the comments.
Even so far everything is ok i had some issues wtih the gantry and i want your opinion
I plan to build the gantry with 2 pieces 120X60X4mm and 2 pieces 80X80X4mm so i would make sometring like that
but i realize that the 120X60 tube is 3mm and not 4mm as i thought. So i think that i may have resonance issues.
TO be more specific at the front of the gantry 10mm steel plate will be welded so finally it will become like this
With 2 pieces of 120X60X3mm tube at the top and the bottom and 4 spacers 120X60X3mm 160mm long
Two 80X80x4mm tubes at the top and bottom and a 120X60X3mm at the middle. May move the 120X60 tube 2cm to the back so to have room for the balnut flange
All thre plans will have the front 10mm steel plate as shown at plan A
All three palns have 280mm gantry height
Three 80X80X4mm tubes with the middle tube offset by 4cm to leave room for the ballnut. This will reduce the gantry height to 240mm and i dont know if it will weaken the machine.
So my questions are
1. which of the above plans would be better?
2. Assuming i will put the rails at the front do you think i can reduce the gantry height ( according to my plans it should be 280mm and nearly this should be the distance between the out face of the carriages of y axis). Plan D reduces the gantry height to 240mm. Remember that the length of the gantry is 1160mm.
Thanks for you time
Last edited by ba99297; 24-07-2014 at 10:01 PM.The creative adult, is the child who survived
Dont be in a rush with it. better think it again. from various angles.
Now a couple of questions which are related:
-Why the 280mm height? Did you purchase already the rails for the Z at certain length?
-what is the width of the Z carriage plate that slides on the gantry?
Because i believe that it can be made narrower and that bearings with some thought to go behind the Z, not to eat of your Z travel left right/x axis/.
-what about the total weight of the gantry? you are not going with servos, right? this frontal plate will weight a lot. Actually i don't like it for that reason. You can strengthen the gantry in other ways. For example plan B and fit triangles inside where the vertical pieces are and no face plate. If the vertical pieces are spaced ~30cm or less there will be no need at all for face plate.
I was personally for plan B, but... Check again all the details, may be a mix of them all. Cause now looking at my drawings in fact i see B impossible as you draw it, cause you only need 40mm of the ball screw support to go inside so the ball screw housing barely shows, but in that case the rails should go inside the profile, which is impossible. So may be draw it first. To me it seems that C is closest of all to the measures . Just move back the middle piece so its 43mm back from the front.
You can reinforce it like this/ the middle profile in your case/ :
I cant remember if you have already bought the ball screws and the rails, if not-fit that motor inside as i told you at the beginning :-) and save some money for beer :-)
Sylyavski i answer your questions to make things clear
The 280mm height is the result of the conevrsations that i had at this thread. They advice me to have minimum distance betwen the outer face of the carriages 250mm. So i make combinations wtih 120X60 and 80X80 tubes to get that height. So two tubes 120X60 at the top and bottom and two 80X80 give me the 280mm
The width of the z axis carriage plate is 370mm. Even if i narrow it as you suggested, i wont get more y axis travel as the spindle plate will conflict with the bottom steel plate ( where x axis carriages will be bolted.
The total weight of the gantry so far is nearly 140 kgr
I will use servos. 4 yaskawa sgmph 400 watt each ( two of them for x axis). 2010 ballscrews for x and y axis, 1605 for Z. 2:1 geat ratio for all axis ( 2 at the ballscrew 1 at the motor. Htd 15 with 5mm pitch aluminum pulleys.
Rails carriages, ballscrews, motors and spindle (2,2 kw) are in my hands. So no change can be made at these components.
If there is any suggestion i will be glad to hear
Last edited by ba99297; 25-07-2014 at 03:25 PM.The creative adult, is the child who survived
I get it now. Then maybe you could look at my last post in my next build and consider how I am making my gantry http://www.mycncuk.com/threads/6619-...0346#post60346
May be you would like some of mine ideas which i belive will lead to very strong gantry with no overhang and exclusively made from profiles, like the ones you have. That's the best I have come till now.
Last edited by ba99297; 27-07-2014 at 11:23 PM.The creative adult, is the child who survived
I have to weld the upper 80X80 pieces ( where the rails will rest )
The lower pieces ( over the foots) make i little curve ( nearly 5-6mm ) at the middle as reult of the heating.
So i decided to weld 4 spacers at the corners. Put the upper pieces with spot welding after make everything square and parallel as possible
Here we are
Four spacers 120mm at the corners
Then i put the upper pieces and before i spot weld i try to make everything square. I use the 1160mm pieces (this is th excact distanse that the upper 80X80 pieces should have) that i will use for the gantry, and other parts of the cutting bed to make everything parallel
After having the tubes as parallel as possible i messure the excact distnace and cut the rest of the spacers. Then i spot weld from the middle to the corners. After everything was in place i start to full weld the table. In order to avoid too much heat i make 2-3 cm welds at a time from one spacer to the other and from the on side to the opposite. So i pass along the table 20-55 times( welding and cleaning the welds). In order to have better welding results i rise the table to have better angle
End of the day and after turning the table upside down to full weld all the sides, i think the result is more than acceptable
0.0-0.1 radius ( messured at different spots) the offset between the upper rails and the vertical pieces.
This offset will be zero after epoxy ( ...i hope so )
Next step is to make the tuning foots. That is why i weld a 80mm piece at every leg with a hole in the middle to pass the m18 bolt.
Then the epoxy method will take place
Till now i think it must be nearly 200 kgr. The winch save me from a lot of work
Thansk for your comments
P.s Do you think that the legs should be connected at the lower part of the table?
Last edited by ba99297; 03-08-2014 at 06:21 PM.The creative adult, is the child who survived
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