CNC plasma table build

[acourtjester]

Here is information about building your own CNC Plasma/router table. I built 3 tables in the last year and maybe those whom are interested in building your own will get the boost to start theirs. This is a great project and will enable you to cut parts for projects of metal art things.
I built a 4X4 then a 4X8 table using the same construction methods and you can scale up or down to fit you needs/shop.
Pictures attached are of the 4X4 completed and the 4X8 base frame next to it. Pile of scrapes after cutting parts for table (1/4" steel) that I sold with some of the plans in next post.
Plans info in the classified section on this form
http://www.youtube.com/watch?v=leWjHZe_rcc video of the sliders I developed for the tables.
http://www.youtube.com/watch?v=CY_FW_vxjA0 4X4 table cutting.

have fun
Tom

[acourtjester]

Pictures of a few thing I have cut on the tables.
Dragon was for a sissy bar on my buddy's Harley 883 Iron.

have fun
Tom

[acourtjester]

Something you will need to figure out is the length of the rails for the correct travel on your table. The attached drawing show what needs to be considered for the length of the rail this is for both the X and Y rails. You need to add the width of the slider to the distance from the end of each to the limit trips. Now add this to the distance you want your torch to travel this will give you the total length of the rail.

[acourtjester]

Here are the sliders I develop for my table I used 2 X and 1Y slider. Each had 10 ball bearings that contact the rails that give a ridged guided movements.
Each bearing is on a concentric mounting stud so they are separately adjustable.

[acourtjester]

Most of the weight on the table is from the water table, support grill and the material that is cut. So you want a well supported base that is square and level (added levelers at each leg). Place the legs in from the ends as you don’t want the center to droop when loaded.
The base of the table is built from 2”X 2”X 11 Ga. square tube and2” X 3” X ¼” angle and 2” X 2 “ X ¼” angle. The 2” square rails and the angles need to straight in both directions before you start. If the angle is not straight you can make cuts in the sides to relieve the tension before you weld it to the square tube. I clamp the square tube to a straight base metal (channel, or I beam ect.) this needs to be wide enough to also clamp the angle. I shim the angle at the side of the 2” square in the middle of one side with the 3” side to the square tube. When all is clamped and straight make a series of short weld at the joint of the angle and tube. Allow to cool and then un-clamp it all and flip it over and re-clamp to the base metal again and add short weld to that side. This will form one X rail and repeat to form the other X rail you want them to straight so the slider run true along the full length of the table when completed. I bought a 6’ level from HF to check the assembly of the table base. After the X rails are finished you can start installing the cross bracing and truing up the complete base for the table. I support the X rail with the square tube down and the angle at the top. Cut the 2” X 2” X ¼” angle to the width of your table I notch each end to allow the vertical part of the angle to go past the inside of the 2” side of the 3” X 2” angle base to the X rail. See attached picture. When you are doing this make sure the X rails are level from end to end and to each other. Shim the supporting base to make this true. I do the end cross members first to insure the base is square and level then add the inner cross pieces of angle. Make sure the X rail is not leaning in or out as you want the top of the rails to be level across the top of each rail and to each other. You can add the legs at this point I bolt them to the base. And you can now weld any cuts you made in the angle sides.

[acourtjester]

Each leg should have a caster and a leveler so the table can be moved in to position and then leveled when making cuts for stability. And the legs should have cross bracing I used 1” X ¼” flat stock for bracing.

[acourtjester]

After the legs are attached and braces attached you can move on to assembling the sliders. Flip the table base over so you can have access to the rails. First attach and weld the mounting bracket that connects the X slider to the Y side plate using a piece of angle to insure a 90 degree mount. Since I use chain drive for the X axis attach the bolts that the idler sprocket mount to. Cut and true up 4 spacers for each of the slider tops. The spacers are 3/4" in diameter and about 3/8" to 1/2" thinck and are welded tothe tops of the sliders at each corner as shown in the picture. This is to extend the bearing stud so the bearing is lower on the side of the rail. Then attach on side to the top of an X slider by clamping them to a 2” X 2” square tube. Weld the 2 part together and then clamp the other side of the slider with shims (about 0.100”) install to give you clearance for the slider to move freely. Weld the second side to the top and repeat for the other X slider. The difference between the X and Y sliders if the Y does not have sprocket bolts and is assembled using a 2” X 4” tube AKA Y rail.

[acourtjester]

This is how I adjusted the bearing on the sliders. I machined a ¾” hex to be offset about .240” and for a bearing that had a .471” ID. I drilled the center of the hex and taped it with ¼” 28 threads per inch. These are setup for a 6001RS bearing (rubber seals) which you can get on EBay cheap. It takes 30 of these per table (10 each for 3 sliders).

[acourtjester]

It is time to install the X sliders on the X rails to the Y rail can be positioned and welded in place. Drill 3 hole in the Y attachment brackets on the X sliders so they Y side plates can be mounted. Mark and drill and tap 3 holes in each Y side plate that match the hole in the Y attachment plates. Also position the 2 bolt flange bearing on the Y side plate mark and drill and tap the bolt holes for the bearings. This is for the cross shaft that is used to dirve both sides of the X rail sliders in sync. Install the bearing on the X sliders and adjust them so they move smoothly along the rail the bearing should have light pressure on the rail. They are to act like guides with 10 bearings each you should be able to turn each bearing with you fingers with light friction only.
After both X sliders are mounted bolt the Y side plates to the X sliders using the 3 bolt holes.
Make sure the table base is level in both directions so when you position the Y rail it will be aligned correctly to the table surface. Measure and cut the 2” X 4” rail to fit between the Y plates. I used a long pipe clamp to hole the Y rail to the Y side plates and check all aligments before welding it in place.

[acourtjester]

I did not show the shape of the Y side plate for mounting the Y rail to the X slider. Here it is and the hole is for the cross shaft for the X drive to drive both X sliders at the same time. This makes it so you can drive both sides with one motor and not having to slave another motor for the other side. The motor mounting bracket for the X motor should be welded on at this point also.

[acourtjester]

Next is the Y drive assembly mount they slider on the Y rail and adjust the bearing for smooth movement. I used a 6-1/2” X 12-1/2” X 3/8” aluminum plate for the base of the Z drive assembly. I mounted 2 strips of 1” X 1” X ¼” angle to the base plate by drilling four ¼” holes in the base plate and counter sink them for ¼” X 28 flat head bolts 2 for each angle. See attached pictures and observe the angles clear the bearings on the Y slider. There are 2 pictures shown this mounting was done differently for two different tables either is correct you chose. Next drill and tap the angles to match the plate these angle are to attach the base plate to the Y slider. Bolt the angles to the plate and clamp it to the Y slider be sure the X and Y rails are level. Then level the clamped Z base plate in both directions if this is not done the torch will not cut straight. Tack weld the angles to the Y slide remove the Z base plate. Clamp a short piece of metal to the 2 angles as shown in the picture so the angles do not move while finish welding. Now finish welding the angles to the Y slider using short weld and allow cooling time between welds. You now can construct the Z axis drive and floating head assembly off the table just maintain alignments so when you attach the Z assembly it will be still aligned correctly.

[sportbike]

Nice to see the step by step build.

Nice mix of old craftsmanship and new technology to keep ya sharp!

[acourtjester]

Thanks Sportbike
Back to work on the X drive components on the table. I used a chain drive as it is simple and cheaper then a rack. I used a cross shaft so I did not need a second motor for the X drive (second drive and another power supply) and slaving the two motors together. I set up to run the cross shaft through the Y rail this is the best location its out of the way. I used a 3/4” shaft and 2 bolt pillow block bearings and #35 Chain. On one side I mounted the drive motor and pulley connected to the cross shaft. There is a smaller sprocket on the motor and larger one on the shaft to have a gear reduction. The chain is attached to each end of the table and runs around an idler sprocket to the drive shaft and back to another idler sprocket. The X drive motor needs to be the largest as it moves the move weight on the table. The Y can be smaller and the Z even smaller unless you are also going to use this for milling or routing.

[Rambozo]

Are you using any type of spring or rubber chain tensioners to keep them lash free?
What are your maximum travel speeds?

[acourtjester]

Here are a few pictures of what I do I don't tighten the chain like a guitar string and I have it supported by flat stock so it acts like a rack. I don’t have problems with the 4X4 table but the 4X8 I supported the chain because of the 9' X rail I have. I have a Hyperthrem PM65 so I can run a speed of 200ipm on 14 Ga.
here is a video of that
http://www.youtube.com/watch?v=gW7w9...mQfMwq0KTKpuRw

[sportbike]

Just in case you get bored and need some more ideas...
http://www.homemadetools.net/

[acourtjester]

Here is the Y drive assembly I used rack and gear as it is simple. I also gear reduced the drive for good precision of movement. The drive components are located behind the Y slider to leave room for the Z assembly on the front. I welded small tabs on the back of the rack for mounting it to the Y rail. The rack gear is attached to a shaft that has a larger timing pulley on the top. This shaft is in a bearing housing that can be adjusted to the rack. The motor bracket is welded to the top of the Y slider to with a adjustable motor mount. A smaller pulley is on the motor for the gear reduction of the Y drive. I also attached an arm that is used to attach the cables for both the Y and Z motors and limit/home switches for better tracking.

[acourtjester]

Now the Z drive assembly I used 16mm linear bearings and shafts for the guides on this axis. I bought then from Ebay I bought a 30” shaft a cut it to length 2 long linear bearing (scs16luu) and 4 end supports. I used 3/8” aluminum plates one it mounted to the Y slider and the other moves up/down and the floating head is attached to it. I used a ½” acme threaded rod and a plastic lead screw nut coupled to the motor for drive. Be sure the assemble moves 90 degrees from the table and the Y axis so the torch cuts straight. Shown in the picture is the limit/home switch.

[acourtjester]

The floating head assembly is simple it is a linear slide, base plate, bar with torch mounting rings attached and the switch. The base plate is drilled to mount on the moving part of the Z axis the linear slide mounts to that and the torch mount bolts to that. There is a bolt I machined (bigger bolt in middle of picture) to go into the slide mount to form a lower stop position. When the Z drives down and touches the surface of the metal It moves off the stop and trips the switch and triggers Mach. Mach backs off and the torch drops back to the stop this is all gravity no spring return needed. There is a screw that contacts the switch so the sensitivity is adjusted for the switch you want a very small movement to trip the switch. I found that the rings that hold the torch (1.375”) fit both a Trafimet P-81 and Hyperthern Duramax machine torches.

[acourtjester]

Here are pictures of my electronics controller all in one box. Box has computer, hard disc, power supplies, drivers, and the BOB board. Keyboard, mouse and monitor are inside the top cover. The controller is mounted on a hand truck type cart for mobility and ease of storage.
Moving on the start another table.