4x8 router 8020 and all the fixins

[coop2005]

Started my build this week on a 4'x8' router made of 8020 and some quality linear drive components. Here are some of the parts I am using

25mm Hiwin Linear rails on all axis
.75" x .5" lead, Roton Ball screws x and y
.625 x .2"lead on z
welded steel 2" square tubing frame
8020 table frame and gantry assembly

thinking im going to use keling servo motors on all axis most likely the largest servos they have for the x and y and drop down a few sizes for the z.

Pictures are of the overall design. Keeping in mind the z axis isnt worked out yet still in the design stage. I initially was going to mount the y rails on the gantry, on the plane perpendicular to the table. But decided that by mounting them on the top and bottom of cross members the z axis assembly will move back a few inches giving me less moment on the x axis bearings. Also im thinking becuase of this the cross members can be shortened so that they do not extend pass the gantry uprights cleaning up the design a bit.

I will post pictures of the build so far tomorrow.

[cabnet636]

let me express my interest in your project
i am almost ready to build
cabnet
www.mcgrewwoodwork.com

[coop2005]

Here are some pictures of the first day of building. Sorry for the poor quality of the later ones, the battery in my digital cam ran out had to use my phone.

The one picture shows (althought very dark) the method i used for insuring the rails were straight relative to the 8020 frame rails.

I recieved the ball screws the other day now i have to try and turn down the ends of the y axis. The x axis is going to have a rotating nut. Due to its length of 9 feet rotating the screw was not an option. The pictures in the first post have some details on how i hope to achieve this.

[cabnet636]

i am studying all of this please keep details rolling and get some sleep
the biggest mistakes i make are when i work until i screw up the do it all over
cabnet

[rayditutto]

i'm very interested (i'm also in canada) in your parts and material sourcing
your build looks like it's off to a good start

[coop2005]

At first glance im not entirely that satisfied with the roton ball screws. Althought they appear very effiecient there is an awful lot of play. Without mounting them and driving them with a dial attached i cant tell how much is actually axial play (lash). I got them to put the larger balls in the nuts which from what i hear, that will give me around .003", we shall see. Im a design engineer in the nuclear industry where money is no object in the design process. The high quality of components i usually encouter may have me expecting more.

[coop2005]

Just bought a router today, Craftsman (Sears Brand), 12000-25000 variable speed, 11 amp, 2hp, soft start. Has built in led work light in the main casing which is an interesting feature for this application. Also 2 year warranty. for $129 CAD i couldnt pass. It looks alot like the porter cable because it has the metal cylindrical casing, this was something that seems critical to me for assuring a rigid mount.

[cabnet636]

we're watchin

are you usibg anyones plane or are these your's

cabnet

[coop2005]

Those models shown there are mine I spent some time before starting the design process looking at a few other 8020 type machines and took some ideas from them. The one thing i wanted to try and achieve that i havent been able to get any feedback from was the rotating nut. I havent found anyone that has tried this in a diy type machine. I have some of the parts made for that assembly, this week im hoping to get that finished.

Im starting to convince myself that i may need to get a second set of ball nuts and preload these axis.

[acondit]

Take a look at this thread. Dan Kemp (Hoss26) built a rotating nut for his z-axis.
http://www.cnczone.com/forums/benchtop_machines/30385-x2_cnc_finished_now_maybe-post370663.html

Alan

[MRM RCModels]

Just signing on and admiring your CAD skills

[lgalla]

Coop,I have been following the rotating nut posts for a while.Are you incorporating A/C bearings in the nut drive?Here is rotons suggested ballscrew uses.
* hospital beds
* medical examination equipment
* servo drives
* log splitters
* dish antenna drives
* door actuators
* scanners and test equipment
* plotters
* robotics
* web tensioners
* automatic pilots
* trim tab drives
* back gage positioners
* fork lift remote
I assume they are not designed for critical applications.
Larry