[matth]

Well I have finally started to build my router. The plan is for it to cut wood and aluminium. Here is a parts run down for the different axis:

X axis:
6 x 300mm 12mm THK rails with 6 x carridges
2 x 400 Oz/in Nema 34 steppers
1 x 800mm 25mm balscrew with two nuts

Y axis:
2 x 520mm 12mm THK rails with 4 x carridges
1 x 380 Oz/in Nema 34 stepper
1 x 350mm 25mm ballscrew with 2 x nuts

Z axis:
2 x 200mm 9mm THK rails with 4 x carridges
1 x 250 Oz/in Nema stepper
1 x 150mm 16mm Ballscrew with 1 x nut

The main frame work wil be completed using 44mm aluminium box section 3.2mm wall thickness.

[matth]

Here is the work that has been done on the y & z axis:

[ViperTX]

I wouldn't have used the 12mm parts, but I'm intersted in seeing what your experience is. Looks like you've done some nice work.

[matth]

I hear you on the 12mm, unfortunitly rails are hard to come by for a good price in the UK so its use what you can. Its because of the 12mm rails that the Y axis is using one rails on top and one below (trying to spread the load into the structure as much as possible). The Z is using 9mm rails! But these seem to be holding up very well without any noticable deflection.

[svenakela]

It shouldn't be a big problem with the 9's and 12's as long as you're not going to cut harder stuff. The rails are holding for very high loads even though they are small, somehwere between 2 and 4 kN per wagon. Make sure to mount them as far as possible and it would work.
And hey, if they would break - then fix it!

--Sven

[matth]

Well, progress stalled for a little while as I am waiting on some aluminium sheet and box section.
Whilst I have been waiting I started to reconsider the usage requirements for this machine. I have decided that the working envelope is just to small for what I'd like to acheive (cutting acrylic for custom marine fish tank sumps, aluminium for 1/6 scale rc car parts and general wood work). 4' x 2' would allow me to cut 1/4 sections of full size standard sheets.
To this end I have purchased some more parts for the x axis and will use the parts from the old plan to increase the size of the y axis. The z axis carridge will remain the same but I have also sourced a very heavy duty 270mm rail that I may use to redesign the slide assembly (this rail is 42mm wide!!).
So whilst I'm waiting on the main parts shown below to arrive from Germany I will work on the y axis (as soon as my aluminium turns up).
I'll keep you updated!

[matth]

I have now purchased the last componant needed for the revised layout. Once all my parts arrive I will start the assembly in earnest.

[matth]

Still waiting on my parts for the X axis but I have now started on the longer Y and revised Z.
The Y is using the same arrangement as before but is using the longer rails from the old X axis design, it is also using a "mount and play" ballscrew assembly form jimonchan on Ebay (excellent product, price and service).
The new Z is using a single heavy duty (43mm) IKO rail instead of the previous 2 9mm THK rails. I'm hoping that it should be stronger with less flex than the old design even though its only using one carridge. Nest steps are to make up the back plate of the Y axis and the ballnut attachement plate and then build the Y motor mount. Stay tuned!

[matth]

More happening, slowly but surely.
The Z axis motor mount has now been made and tomorow I will hopefully finish the Z all together. To connect to the box section I have made a small aluminium block to slot into the end of the box section and allow everything to be bolted together.

[jimbo]

looking real nice. keep the updates coming.

on your z, it doesnt look like you have any thrust bearings and have the motor coupled directly to the ballscrew. this may work for a little while but the bearings in the motor are not meant to take thrust loads.

[matth]

Very good point Jimbo, I had not considered that!
I will add a L plate to the bottom of the screw and bore a recess for a skate bearing (I know their not for thrust loads but it can be replaced easily).
I'll post some pics of this tomorrow.

[matth]

Question:

I'm currently considering my last purchase which is the material for the X axis supports. The sides of the machine will be roughly 2 metres longwith a support at each end, the 1.8 metre rails will be bolted to the sides. I have a bunch of 2" x 2" X 10G and 1" x 4" x 10G box section so I'd like to use something that will match up with this well.

The options are:

1" x 4" X 10G box section (mounted vertically)
1/2" x 4" solid bar
2" x 2" solid Bar

The cheapest and simplest option is the box section, any opinions out there on the suitibility of these materials??

[matth]

Right, time to get back on this horse!

I finally decided on 6" x 2" aluminium RHS for my main rails.
Now that I have the materials I thought it best to put together a model.
Watch this space for updates!

[matth]

Right, finally some movement on this project. The YZ axis have now been bolted together to form the gantry (I wanted to build the gantry first so I could dimension the frame properly). The box section is bolted together using solid aluminium blocks in the ends. All that is left to do on the gantry is to make the router plate and build the x axis nut carrier.
I am currently working on sizing the peices of the frame, the 4 main sides are 6" x 2" and the table supports are 1.75" x 1.75".
The pic with the rails attached shows the rough side of the finished router.

[joecnc2006]

is that a one turn per inch leadscrew?

[matth]

Leadscrew is 20mm per turn.

Almost finished the frame, working on all the pieces at the moment so it should all come together really fast!
Here are some pics to show how I am joining the box section together. You can also see the x axis ballscrew bearing carrier installed through the crossmember.

[matth]

Working on the main x axis support members tonight so hopefully should see it all bolted together tomorrow. Here are some pictures of the cross members and ballscrew mocked up. For some sense of scale just remember that the x rails are nearly 2 metres long:

[bret4]

What do you plan to use for the table?

[matth]

Oringinally I was thinking along the lines of a sheet of 1" marine ply, but now the machine is coming along I am considering a quarter sheet of 10mm aluminium (i'll see how the money goes!).

Here are yet more pics of how it is all coming together. Tonight I have drilled the main rails and bolted in the main crossmembers, the gantry is just sat there to give me an idea of the finished look. The main rails are actually bolted on around the wrong way, the larger overhang should be at the end that the motor will bolt to, I will correct this when I drill the rails for the smaller cross members.

[bret4]

I have been thinking alot about what to make the table out of on the machine I want to make. A lot of people use MDF for their tables. I wouldn't think about going with 25mm aluminum if I were going to cut a lot of aluminum.

One of my thoughts about going with MDF is that you can skim cut it with the machine so it is flat with the head. Another advantage is that if you cut into it by mistake you will not feel as bad as on a expensive aluminum table. My local home center has MDF already cut to 2' X 4'. That makes it easy.

One of the things I am wondering is how to size the stepper motors for the machine. I see you are going with 400 in oz motors. I am going to cut mostly plastic and still have to figure what size to use and what control to use. Thinking of using the gecko Drives.

The side plates on your gantry look a little thin to me. I would be worried about flexing when cutting. I would think 25mm or better would be a good thickness. I am thinking of using some 5" X 2 1/4" for the up rights on the gantry.

All in all your machine looks really cool! Close to just what I want to make.