Help and guidence with new desing

[Sturmer]

Hi there, after a few years in the dark finally i got an opportunity to design and make my own small size router. The desing demands are only to cut in soft materials (extreme would be aluminum), and engraving on gravo-plast.

In the attachment i give you the PDF file that has 3D model made in Alibre design, any advices and ideas are appreciated (the design is about 80% complete).

For , the electronics i intended to use 387 OZ motors, and GECKO 540 drive ( this order)

And linear guides & screws from SKF

And when the build starts, il try to make full build log.

PDF file and Some Renderings can be downloaded here

http://www.mediafire.com/?lhu0jeoauoxpczk

[CarveOne]

Originally Posted by Sturmer Hi there, after a few years in the dark finally i got an opportunity to design and make my own small size router. The desing demands are only to cut in soft materials (extreme would be aluminum), and engraving on gravo-plast. In the attachment i give you the PDF file that has 3D model made in Alibre design, any advices and ideas are appreciated (the design is about 80% complete). For , the electronics i intended to use 387 OZ motors, and GECKO 540 drive ( this order) And linear guides & screws from SKF And when the build starts, il try to make full build log. PDF file and Some Renderings can be downloaded here http://www.mediafire.com/?lhu0jeoauoxpczk

Very nice looking renderings Sturmer, and a very clean looking design.

Are you driving just one side of the machine or is there a drive belt or chain under the table to connect the motor to a lead screw on the other side? Driving from one side only will give problems with gantry "racking".

I only looked at the renderings so far.

CarveOne

[Sturmer]

Hm..well i thought to drive it just form one side... (no chain or belt..).Why do you think that i will have the problems with this design, as i said i dont expect big forces of cutting and if i will have a need to cut something stronger il just do it in few more passes of tool.

Im, still working on Z -axies,and on the tool holder so there will be for sure a few changes in the design. Oh, and im trying to make the design as clean as possible by using only two types of bolts,and epoxy resin. So the whole design would be as it can get to build when you have all the parts.

[Sturmer]

OH!! Sorry i just now saw that the renderings have an BIG mistake, in the desing the motor is placed in the middle of the y axies not on th side ( now i understand your commnent better.... sorry it's just error that happens from time to time while exporting the model in tho the STP format. The motor is placed in on the bracket that can be seen in front and at the back of the machine ( 5 holes in the middle)

[CarveOne]

Originally Posted by Sturmer Hm..well i thought to drive it just form one side... (no chain or belt..).Why do you think that i will have the problems with this design, as i said i dont expect big forces of cutting and if i will have a need to cut something stronger il just do it in few more passes of tool. Im, still working on Z -axies,and on the tool holder so there will be for sure a few changes in the design. Oh, and im trying to make the design as clean as possible by using only two types of bolts,and epoxy resin. So the whole design would be as it can get to build when you have all the parts.

Driving these machines from just one side is not considered to be a good plan because even a small force on the end of the gantry away from the driving lead screw will be multiplied into misalignment of the gantry. Of course, you can try it if you wish to, but be prepared to fix it if you run into the problems that other people have experienced with this idea. Center drive is recommended, or use two motors and slave them in Mach3.

I'm just bringing it to your attention.

CarveOne

[Sturmer]

Originally Posted by CarveOne Driving these machines from just one side is not considered to be a good plan because even a small force on the end of the gantry away from the driving lead screw will be multiplied into misalignment of the gantry. Of course, you can try it if you wish to, but be prepared to fix it if you run into the problems that other people have experienced with this idea. Center drive is recommended, or use two motors and slave them in Mach3. I'm just bringing it to your attention. CarveOne

If i understood you correctly you mean like this... (this is the the true design of the y axis in the middle of the y table is the screw) but in the first renderings i have had an issue with the conversion from alibre format of the file to stl.

And what do you think about the backlash, and the strength of the motors will it suffice the intended purpose.

Many thnx for the advices, they are greatly appreciated!


PS. Im sorry for any English spelling errors or verb forms as im not natural speaker.


(this is how is intended to be made - notice the motor in the middle of the y table)

[CarveOne]

Originally Posted by Sturmer If i understood you correctly you mean like this... (this is the the true design of the y axis in the middle of the y table is the screw) but in the first renderings i have had an issue with the conversion from alibre format of the file to stl. And what do you think about the backlash, and the strength of the motors will it suffice the intended purpose. Many thnx for the advices, they are greatly appreciated! PS. Im sorry for any English spelling errors or verb forms as im not natural speaker. (this is how is intended to be made - notice the motor in the middle of the y table)

Your rendering now shows the motor in the center of the table, which is what I referred to as "center drive". This is the most commonly used method for smaller machines that do not have very wide gantries. Center driven gantries also have problems when the gantry width becomes too long.

For the larger machines with wider gantries it is common practice to use a lead screw of some type, or rack and pinion drives, on each side of the table and each side has a motor driving it. The motors are wired so that they run in the same direction, and the control software (Mach3 or EMC2) is configured so that both motors respond to the same commands. This is called "slaving" the drives.

381 or 367 oz-in motors and the G540 are an excellent choice. Use 1/2-10 5 start ACME screws with anti-backlash nuts from DumpsterCNC or the appropriate ball screws. You'll have a fast, powerful machine.

CarveOne

[Sturmer]

Ok, i thought so ( on the first images there was mistake made by converting the file formats so i can render i n Keyshot thats why the motor is on one side not in the center as i intended it to).

Yes i will use ball-screws from SKF

One more question that i have is , as i am using nuts to fasten the different parts, i intended to use the epoxy to make the whole thing more stiffer. Will it suffice?

I hope to finish, the whole design and pricing listing the parts and drawings at least month before the end of the year, so hopefully it will "Run, swimm and purr" before the spring (if all the financial stuff are solved ASAP )

PS.
The building log will surly be made

[CarveOne]

I just looked at your rendering in the PDF file and saw that the table top moves and the gantry is fixed. I just assumed that the gantry moves. I should have looked earlier.

Where do you want to use the epoxy? To join the base plates, to glue the gantry riser plates, or on the crew threads? I wouldn't recommend using epoxy on the screw threads. Use a thread locking product that can allow the screws to be removed later.

CarveOne

[Sturmer]

I meant to use "Locktight" for the screws and the base plates, and "body" of the whole machine (except the place where are the holes) would be epoxied. as construction material i ment to use is Aluminium

[arizonavideo]

If the table moves then their is no reason not to make the gantry sides and cross support as thick and strong as you can.

[Sturmer]

Originally Posted by arizonavideo If the table moves then their is no reason not to make the gantry sides and cross support as thick and strong as you can.

Well general idea was to make additional support , to the gantry but as the design is not finished i cant predict where will what end ( il make some cable gudies and maybe box construction to close(hide) the motors so i have a lot of space for hiding the additional support. Il post as soon as i make some re designing ( i have some issue of what bolts tu use (im trying to use only one type for the whole construction ...) Well see thnx for all of you for the tips