Router build

[JAZZCNC]

a 10mm inside boundry of epoxy with a filler adds about 10 kilos to each beam ... i think it will made a huge difference

im no engineer , and got no idea where to even start to try to calculate the difference in damping .. but it can only make it better

i thinks im gonna give it a try ...

Can't beat filling with dry sand and bonus is it can be removed when need to move the machine.

[Blackrat]

On the gantry ? What's the density ? Wanna see what it's gonna weigh :-)

[JAZZCNC]

On the gantry ? What's the density ? Wanna see what it's gonna weigh :-)

Approx 1250 - 1500 Kg/M3

Don't be afraid of weight in the gantry it can be your friend and give far better surface finish and allow deeper depths of cut. Unless your doing very high feed directional changes then having heavy gantry really does help not hurt.!

[Boyan Silyavski]

While i agree about the weight, after all i managed to make 1000x400x200 machine to weight 200kg, something that i don't see on this and many designs are the ribs. Apart from the careful listening to advice and using quality components, the machine in question is build so that there is not a single part of it that is not insured against bend in any directions. By ribs. Hence the precision achieved.
Also there is not a single detail which gives doubt about weakness. Where it looked weak on the initial design, i designed it so that the weak places were reinforced by smooth transition and angles made so to transmit forces in the direction i liked.


Point that look not right to me on your design:

Ok, you will weld 2 beams together for the gantry, i did the same , but where are the side plates that are soldered to them at both sides. They will bend and if not, they will vibrate. They can not be left open.


Gantry legs. i see one plate in the middle that will reinforce them . One is enough against left right bend, but not against twist. i would put 2 on each leg so they form a box.


Web Goblin, your gantry looks very nice. What you intend to do with the gantry legs? Why you did them like that? You plan to fit the screw there? I contemplated this design for compactness, but for my liking it seems weak for left right forces. I would have reinforced this place with closing the beams and drilling holes from above to fit the screws to the bearing blocks.

[Web Goblin]

I did the frame this way because I thought it would give me the best strength while still getting full travel of the gantry rails. The join between the cross rail and foot plate is fully welded and should be very strong.
The bearing blocks are mounted below the "foot" plate. The bmp from my cad drawing below shows how the blocks will be fitted. The top cross bars are not shown here but they will add more strength for left/right forces. The position for the ballscrews is shown as well. These will be covered as well to try to prevent swarf getting to them.

[Blackrat]

Ok, you will weld 2 beams together for the gantry, i did the same , but where are the side plates that are soldered to them at both sides. They will bend and if not, they will vibrate. They can not be left open.


Gantry legs. i see one plate in the middle that will reinforce them . One is enough against left right bend, but not against twist. i would put 2 on each leg so they form a box.

.

heya silyavski

i agree ! end caps are a must ! i intend to have a few internal webs to prevent twist

im not convinced on this one ... if there was only one arm, then yes for sure , but the other arm of the gantry prevents the twist

i think for now im going to go with filling the frame with sand ... but the gantry , im going to try out a epoxy fill

[Blackrat]

sand with a 1500kgm3 will add 60kgs to the gantry :S

an idea ....

[Blackrat]

Jazz , I do agree ....
Do you feel I should just raise the bearing a bit to have a touch more clearance like Clive suggests ?

I don't find many examples of moving rails ... Got any links ;-)

[Clive S]

Jazz , I do agree ....
Do you feel I should just raise the bearing a bit to have a touch more clearance like Clive suggests ?

I don't find many examples of moving rails ... Got any links ;-)

A lot of people put the z rails on the plate that the spindle fixes to as it helps to stiffen the plate up. ..Clive

[JAZZCNC]

Jazz , I do agree ....
Do you feel I should just raise the bearing a bit to have a touch more clearance like Clive suggests ?

I don't find many examples of moving rails ... Got any links ;-)

No I suggest you have moving rails.!! . . . .The whole idea with any area of the machine is to try and reduce vibration at the tool and moving the bearing higher will just make this worse. Yes you'll have more clearence but you'll get more vibration.

Most machine builds on this forum use moving rails so Check them out.!

To be honest if your just building a Router for cutting wood and soft materials then it's not a problem but if you want to cut harder materials which often require shorter tooling then it does become a problem. Moving rails helps get around this without messing around raising the work or having moving table.

If you want good combination so can cut all materials then have a moving table along with moving rails.