I Finally Got my Machine Built.

[ecmarsh]

Last fall I was back south visiting the kin folks and stopped by planekrazie’s and he had his CNC running. I was really impressed with the things he was doing with it and never saw such a machine before. I had been wanting to build a plastic item for a couple of years but prototyping injection molding was out of my price range plus with my limited ability with CAD there were sure to be many mistakes. Well the wheels started turning and off I went to the next stop.
On the way back to Iowa we stopped by inventorjohn’s in KC and he was constructing a machine. All the parts were there so it was an education for me. I was introduced to 8020 aluminum, stepper motors, G-code, and all that stuff. Within a week the CNC was up and running and I was hooked.

Got back home and started lurking on the zone and searching for any information I could find regarding CNC routers. Ordered a copy of David Steele’s plans and got all kinds of ideas. I ruled out the skate bearings as my drilling and machining ability is next to none. So kept looking on eBay for linear rails and stuff like that. Purchased things from time to time and some I resold as they were not what I thought they were. Ordered the motors and controller from Xylotex so I could play with them on the table as I made plans for the building.

I got the X and Y rails eBay and a good deal on a complete Z axes unit. So I stared at those for awhile and realized it was time to figure out how to start building the thing. I had virtually no tools and a garage full of junk so I ordered a drill press, miter saw, table saw, taps, dies, drills, and on it went. I spent my whole budget on stuff before I even got started building the machine

What I wanted was a machine large enough for a full size router and had good accuracy. I decided on a gantry with a low center of gravity and to tray a belt drive for at least one of the axes. I used a 3x3 t-slot piece for the gantry and bolted it to an aluminum plate that was attached to the Y bearings (I got mine set up X and Y like the computer screen so I don’t have to stand on my head looking at the machine bed.) Faced the t-slot with a 1/8” aluminum plate and mounted the X rails then bolted the Z thing to it. I went and ordered a K-2cnc router mount and am very glad I did. So next was putting the rest of her together.

I went ahead and did some what of a continuous belt for the Y as that seemed much simpler than the mechanism in David’s plans. Very happy with the belt as it is extremely fast and accurate (as far as I can measure). I had purchased a big old ball screw for the X and it seemed to be perfect except slower than molasses. At 6 turns an inch the best I could get out of it was 30 ipm rapid and about 20 ipm cutting and she still would stall the 500 oz stepper with any kind of load. Everything was working perfect except the slow ball screw. I had to change that over to a belt drive. Came up with a good setup and had all the parts except for the belt and pulleys. I went and cut a belt clamp out of nylon as I sure didn’t want to buy another one of those things as they cost more than the belt. Put it all together and away she went. I have the rapid set at 300 ipm and can go much faster but I don’t want anything flying through the air. Se can cut as fast as the Bosh motor can handle it and seems very accurate. For me the belt is the way to go as it is a cheaper setup and well I am happy. That was the only major modification I did to the machine after completing it.
Still have a problem clamping my material level when I work on a full sheet (she is only 24” x 20” cutting area) but I will figure it out as time goes on.

This was a little long winded but I haven’t posted before so trying to make up for lost time. There are some pictures of the building process on my web site if anyone is interested http://www.ecmarsh.com/cnc and I will post more pictures here as time goes on.

Thanks to everyone at the zone for all the ideas and valuable information, Ernie

[Coogrrr]

Awesome job! I too love belts and my thread shows that. I think you did very well for a first time! as for the 8020 and level board issue. try this. I would cut some 2x4's or 4x4's to more than the thickness of the 8020 and replace every other piece of 8020 with wood. that is at least .3 or .5 taller than the 8020. Then take a nice flat bit and router the tops all evenly. dont go too low or you will hit the 8020. The wood will support the project the 8020 that is left will be for tie downs and your good to go!.

OPTION B: this sacrifices Z depth a little but... you can take strips of 1/2" thick woord by 1" wide and t-bolt it to the 8020 cross ways to the 8020. Now repeat that milling step to level them all to the same hieght and walla you have a flat surface and removed no 8020 for locking down needs.

I intend on useing an all wood bed that has many holes drilled and then t-nuts up throught the back for my bolts to go down into. I will place sacraficial strips of wood on top and mill those all down evenly.

I like t-slotting and I think it is very much the way to go but the investment will cause that to wait for me and when I do get it well hell I will have a hundred holes to bolt it down to!


Coog

[ecmarsh]

Hi Coog,
Thanks for the compliment; I am very happy with how it turned out except my deck leveling problem. Looks like your option A is going to do the job for me. I am going to town tomorrow and get a couple of 2x4s and get it done.
I have been racking the old brain trying to come up with something where I could still lay a larger sheet than my cutting area on the table and this is it.
I will let you know how she comes out and I know it will work.

Thanks very much, Ernie

[Coogrrr]

Your at the store now! Well thats what I assume. Glad to be of help, God only knows how many people on this board have helped me!

Coog

[ecmarsh]

Didn’t have any luck shopping friday. My business with HD has ended, nuff said on that one. Will hook up the trailer and go 35 miles in the other direction and get my supplies from Menards or Fleet Farm either today or Monday. Will let you know when I get it done.

Ernie

[randyf1965]

I hear you on that.. I prefer Menards over HD. Menards always seems to have the parts I need unlike HD which always has stuff I don't need or want. OR the help just walks by never asking if they can help you and when asked if they can help say it's not their department and walk off. Luckily I have a Menards on my way home from work!