Page 8 of 22 FirstFirst ... 67891018 ... LastLast
  1. #71
    Hi,
    my intent was not to confuse you, but to point you that aluminum plates bolted to the steel profile is in no way different than aligning rails to steel gantry. Also that you need to machine it or find somebody to machine it precisely.

    You should choose what ever method is easier for you to make or order.

  2. #72
    Silyavski i didnt mean that you confuse me ,i just cant decide what is better for the kind of macine i am trying to construct. Steel looks for me a better choice as aluminium will raise the cost

  3. #73
    One basic question
    If i choose aluminium as the basic material of the gantry, could i have 6-10mm holes laser cutted at a 20mm aluminium plate. They told me that there is a "law" that says that you cant laser cut holes smaller than the thickness of the material. Is that true ? That means if i have a 10mm thickness steel i will have 10mm laser cutted holes, accordingling about aluminium.
    Thanks

    Vagelis

  4. #74
    Quote Originally Posted by ba99297 View Post
    One basic question
    If i choose aluminium as the basic material of the gantry, could i have 6-10mm holes laser cutted at a 20mm aluminium plate. They told me that there is a "law" that says that you cant laser cut holes smaller than the thickness of the material. Is that true ? That means if i have a 10mm thickness steel i will have 10mm laser cutted holes, accordingling about aluminium.
    Thanks

    Vagelis
    If the laser cut service told you - its so. In 10mm steel there is no problem to cut 5mm holes. But anyway, they could mark you the holes with the laser, so later you drill them. Normally the laser cut service would have a mill also, so they could drill you the holes, once marked.

  5. #75
    So far i understood that i should go even with all steel or all aluminium gantry, as combination of these materials will be a little tricky.
    I will ask one more time and if somebody reading the thread i will be glad to hear his opinion. In what directions i must have the ability to adjust
    FOr example if i go for all steel gantry, all parts welded and epoxy leveled for y axis rails, also epoxy leveled for the plates that will be bolted on the carriages what are the spots that should not be welded but bolted in order to have the ability to adjust?

  6. #76
    After over a month of inactivity i come back. Just one question before upload some resent photos.
    For 2010 ballscrew should i use BF/Bk 15 or BF/BK 17 ?

    Thanks

  7. #77
    Quote Originally Posted by ba99297 View Post
    For 2010 ballscrew should i use BF/Bk 15 or BF/BK 17 ?
    BK15 Vagelis.

  8. #78
    Hello everybody. I came back to show my little progress.
    I want to remind everyone that we are talking about a cnc router with

    X 1800mm
    Y 1000mm
    Z:300mm

    It will be moved with 4 ( 2 x axis, 1 Y axis, 1 Z axis ) 400 watt yaskawa servo sigma II.
    Steel is the basic material for the construction ( except z axis that I didn’t design yet )
    As the table has been discussed many times, I have nothing to say. I just upload two photos . Basic beam is 80X80X4 mm.

    Click image for larger version. 

Name:	isometric.JPG 
Views:	168 
Size:	402.9 KB 
ID:	11947 Click image for larger version. 

Name:	total 1.JPG 
Views:	166 
Size:	281.3 KB 
ID:	11946

    The gantry will be maid from two 120X60 X ( 3mm or 4mm thick steel ). At the end of the gantry frame, 8mm and 10mm steel plates will be welded in order to reinforce the gantry attachment to the side braces that will be bolted on the carriages.
    Click image for larger version. 

Name:	gantry 1.JPG 
Views:	155 
Size:	194.2 KB 
ID:	11948 Click image for larger version. 

Name:	gantry back.JPG 
Views:	142 
Size:	201.2 KB 
ID:	11949Click image for larger version. 

Name:	gantry down.JPG 
Views:	152 
Size:	202.5 KB 
ID:	11959Click image for larger version. 

Name:	gantry sides back.JPG 
Views:	277 
Size:	273.0 KB 
ID:	11960




    If it will be needed ( I try to avoid it ) the front face and the side (left-right ) faces will be perfectly milled to be vertical each other.

    Here I want your opinion about the way I laser cut the steel plate and the way I try to keep everything square in order to avoid (if possible) machining cost. If you notice the plates has been cut in such a way ( like a puzzle ) that it is difficult to distort when I will weld them ( I am planning to tig weld the parts in order to reduce heat distortion). Do you think this trick ( “ puzzle cut “ ) will work ?

    Click image for larger version. 

Name:	puzzle 1.JPG 
Views:	148 
Size:	69.3 KB 
ID:	11950

    The same way I made the side braces here are some photos.

    Click image for larger version. 

Name:	side brace build 1.JPG 
Views:	131 
Size:	138.5 KB 
ID:	11951Click image for larger version. 

Name:	side brace build 2.JPG 
Views:	123 
Size:	130.0 KB 
ID:	11952



    If you notice the side braces have straight slots in order to fine tune the gantry so I will be parallel to the cutting surface.

    Click image for larger version. 

Name:	side inner.JPG 
Views:	129 
Size:	167.5 KB 
ID:	11953Click image for larger version. 

Name:	side inner 2.JPG 
Views:	120 
Size:	119.4 KB 
ID:	11954Click image for larger version. 

Name:	side brace.JPG 
Views:	150 
Size:	198.6 KB 
ID:	11961

    At the following photo you can see two holes where I will bolt screws that will help me to adjust gantry height.

    Click image for larger version. 

Name:	gantry sides tune holes.JPG 
Views:	138 
Size:	73.6 KB 
ID:	11955

    Also the straight slots ( on the vertical piece of the side braces ) will allow small ( up-down ) movements. Side braces and gantry frame will be bolted together.

    Click image for larger version. 

Name:	gantry sides front.JPG 
Views:	173 
Size:	196.7 KB 
ID:	11956

    As for the ball screw mounts, they are also adjustable.
    Click image for larger version. 

Name:	bk mount.JPG 
Views:	157 
Size:	310.5 KB 
ID:	11957Click image for larger version. 

Name:	bf ballscrew mount.JPG 
Views:	153 
Size:	660.3 KB 
ID:	11958

    I want your comments if you wish , an I remind you my basic questions
    Click image for larger version. 

Name:	total isometric .JPG 
Views:	202 
Size:	545.8 KB 
ID:	11962
    1. Is the gantry overbuild?
    2. Is 10mm steel ( for gantry side braces, front face, and side reinforcing )too much for such a construction or should I go with 8mm 7mm or 6mm. I am asking because if we follow the 1:3 relation between steel and aluminum, 10mm steel equals to 30mm aluminum )
    3. Will the puzzle cut technique work?

    As for the weight the gantry without the motor that will move y axis and without the ballscrew and of course Z axis, weights nearly 41 kgr ( with 10mm thick steel for the side braces and 8mm steel for the reinforce angles and 4mm 120X60 rectangular beam). If I reduce steel thickness and remove steel from some no critical spots, it is obvious that 41 will be easily reduced to 35 or less.


    Thanks for your time

    Vagelis

    Ps: I will use 1:2 gearing but at the above plans i use 100mm 60 tooth diameter for the ballscrew pulley ( that will give me 1:3 gearing, having in mind that the motor pulley is nearly 3,6mm 20 tooth) in order not to have dimension issues if in the future i want to go with 1:3 gearing.
    Last edited by ba99297; 30-03-2014 at 09:55 PM.

  9. #79
    Forget all the cutouts on the gantry which have been included to reduce its mass. The servos you have a plenty powerful enough to move achieve the required dynamic performance for a gantry several times heavier than what you have designed. If you continue with your plan to use 100mm diameter pulleys then the inertia of just one of those pulleys will be more than the equivalent inertia of all three axes! Decide on the rapid feedrate you want, work out what drive ratio is required, select pulleys, then check that the servo motors are capable of driving it with the required acceleration. It is very simple to calculate, so don't compromise the performance of the system by using very large pulleys when they're almost certainly not required. If you're not sure how to work it out then let me know and I'll show you.

    In answer to your direct questions:

    1. Depends what you want to do with it, but you seem to be in the right ball park.
    2. The consequences of using a lower thickness and having to replace it are far worse than the small increase in cost to use 10mm, so unless you're prepared to calculate it just stick with the thickest you're happy to pay for (presumably 10mm).
    3. It looks a bit risky to me - the tolerances on the parts would have to be very good for them to fit together properly.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  10. #80
    Jonathan thanks for your responce.
    As for the pulleys i am planning to use the following setup

    X axis: 2 X 2010 ballscrews 1500mm long with 2:1 gear
    Yaxis: 1 x 2010 ballscrews 1000mm long with 2:1 gear
    Z axis: 1 x 2005 ballscrews 350mm long with 2:1 gear

    As for the speed calculations i have made this thread

    http://www.mycncuk.com/forums/gantry...culations.html

    So with 2010 ballscrew and 2:1 gear ratio

    i will have

    motor gear ratio 1
    ballscrew gear ratio 2
    ballscrew length 1500
    ballscrew diameter 20
    ballscrew pitch 10
    ballscrew rpm 1500
    ballscrew rpm threshold ~1200
    rapids mm 15000


    Vagelis
    Last edited by ba99297; 30-03-2014 at 11:06 PM.

Page 8 of 22 FirstFirst ... 67891018 ... LastLast

Similar Threads

  1. BUILD LOG: New build.Stell frame cnc 1500X1000.Ball screw and gearing calculations
    By ba99297 in forum DIY Router Build Logs
    Replies: 12
    Last Post: 03-09-2013, 10:37 PM
  2. Adjustable spindle mount?
    By cncJim in forum Marketplace Discussion
    Replies: 2
    Last Post: 19-06-2013, 08:58 PM
  3. Your Opinion
    By PWD in forum Milling Machines, Builds & Conversions
    Replies: 4
    Last Post: 22-05-2012, 11:02 AM
  4. Opinion about the structure of the router ...
    By C.AlveSilva in forum Gantry/Router Machines & Building
    Replies: 11
    Last Post: 01-05-2012, 02:03 PM
  5. WANTED: adjustable tailstock
    By johngoodrich in forum Items Wanted
    Replies: 0
    Last Post: 29-03-2012, 07:38 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •