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Splints router build log
Hi Gang,
for quiet some time now I have been working on and off on my first router. Over the xmas break I have been working on it full time and hope to have it completed and working in the very near future.
My primary reason for building a cnc router was to be able to quickly and accurately make my own foundry patterns, and with that in mind I designed it with a reasonably large z travel (280mm) and will be using an electric die grinder with an extended "snout" to have a better ability to work in confined pockets. A secondary reason for the long z travel was to build it with the ability to use it as a starting point for a four axis and then a five axis machine at a later point in time.
It will be a servo driven system using Electrocraft E543 motors with 1024 cpr encoders and will use Rutex 2010 drives and Isel rolled ballscrews. I hope to be able to get rapids speeds of about 100ipm.
The table is 1800 long (1550mm x travel) and a bit over a meter wide (990mm y travel).
Anyway, nuff talk for now, here are some pictures of the construction of the table.
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I just got one word to say to you.
ABOUT TIME ! ( actually two words )
Thanks for the encouragement yennb....I hope you realise that in order to make space to store this machine once completed I actually had to buy a house, then once I had the house I took full advantage of the silly amounts of overtime going at work and was regularly doing 90 hour weeks so no time for building a router...
Anyway getting back to the story, the x and y axies are based around a 200 by 250 by 20mm alloy plate which has 10mm angle plate bolted to it. The angle plate will be the mounting point for v blocks which will run skate bearings, the whole assembly will roll on 3/4" chrome plated hydrolic ram bar, and there will be plates bolted to the end of the angle plates to control any spreading effectof the angle plates while in opperation.
As you can see in the picture, prior to drilling the holes in the plate I laid the angle plates in their positions and marked the holes with a texta so that if I misread the dro or the plans I would pick up the error prior to drilling holes.
Here are some more pictures of the construction. One of the side plates is shown, there will be a plate run across the bottom, below the table where the x axis ballnut will mount (centerally).
To the left of the side plate is the two rails which will sit in vees machined in an aluminium plate. This will be used for the z axis, which will be quiet narrow, marginally narrower than the die grinders case to allow for movement into confined spaces.
The y axis plate is mounted in the vise on the mill and has had the bolt holes drilled and tapped for the rails to be mounted in.
The other componants are the mounting brakets for the x axis v blocks, the lower section of the z axis where the snout of the die grinder locates and the side braces to assist with lateral rigidity of the side plates.
The electrical system is the remains of a small mig welder which I got from a guy who repares welders, he took of the wire feed, leads and gun and i got the rest with a few big caps. I put a few more turns on the secondry winding to get the desired voltage and I was in business. Allthough as far as power supplies go, this is overkill, even if I go for a full 5 axis machine and all motors are pulling maximum amps at the same time there will still be plenty in reserve. The main reason I went this way was because of the price (far less than the cost of new componants if I were to build one of my own) and the simplicity of having a working system ready to go.
The biggest issue for many Aussies is there is such limited availability of second hand cnc gear and the price of such gear is high (that's if you can even find what you want) fortunately I picked up my servos at a reasonable price when I was in Singapore at Kaichin Electronics who deal in used industrial electronics and hardware.
As mentioned earlier the servo drives are Rutex 2010s and I opted for an optoiscolated motherboard to protect the pc. Unfortunately I accidentally hooked up the power supply wires to a board reverse polarity and let the smoke out. The pc I got from a computer swap meet, it's a pentium 2 gig.
It is nice to get some spare time I bet, 90 hours does not leave much left, however it looks like you are making up for it now, looks great.
I hope you find time to share some close up pictures of the Rutex 2010's and associated connections. That is a ways away for me yet and I have been reading up on it to get some mental understanding but actual pictures would be a real help and time saver.
Ken
Splint
Keep the posts coming - fantastic work.
I know what you mean about limited materials and high prices. I have been sourcing bits from Singapore as well - it seems like the best place for used gear over this side of the world.
cheers,
Rod
Perth, Western Australia
The pulleys are AT5 type which is a more precision version of T5 pulleys (less backlash between the belt and pulley) the belts are synchroflex brand, not sure where they are made, possibly here in Australia. The energychain is Kabelschlepp microtrac http://www.kabelschlepp.com/miva/mer...gory_Code=CHCS Igus also has a good range of energy chain but Kabelschlepp was cheaper.
Here are some close ups of the Rutex system. The first image is the optoiscolated motherboard with a 2010 drive plugged in. I bench tested it like this and used the Rutex tuning software, if you follow the instructions it's pretty easy.
The next image is a closer look at the 2010 drive.
The last image is the single ended line driver. The encoder is wired to the screw terminals (pos, neg A and B) and then a network cable runs between the line driver and the 2010 drive.
This image shows the ballscrew which is 16mm with a 2.5 mm pitch which will be the spec for the y and z axies. The x will use a 16mm diameter with a 5mm pitch to halve the rpm of the screw to reduce the whipping effect which will be caused by its considerable length.
The ball nut, seals and housing are also shown. The housing has two grub screws in it, one at the end to lock the nut into the housing and another at the centre to tension the nut. The nut has a cut out section which has a shim device in it, once the screw is in the nut the tensioner screw is tightened until the shim bottoms out and once the nut is lubricated through the grease nipple on the nut mount it is ready for use. The shaft through the nut is a dummy shaft which remains in place until the nut is fitted to the shaft, this prevents the balls from dropping out.
Last edited by Splint; 12-25-2005 at 05:23 AM. Reason: Forgot to put the image in.
Hey Splint, When you said you where building your machine in your PM to me I didn't expect what I found in your log. Don't beleive in starting small hey.
Will keep uptodate of your progress, will have to go back to my humble shed and keep building my TOY.
Later
Prboz
Do you have any singapore web sites for equipment?
Thanks
A search found this
http://cnczone.com/forums/showthread.php?t=3125&page=5
I have sent you a PM with more details.
Hope it helps
cheers,
Rod
Perth, Western Australia
Hi Prboz,
I guess "big" is relative, you should see some of the mosters used in the marine and aviation industries, I'm talking work envelopes of 50 by 12 by 8 meters, that's big.
Ebay has several stores in Singapore who specialise in cnc hardware but that's all I know of. Kaichin, to the best of my knowledge dose not have a web site.
Here is an image of the die grinder I will be using. The base of the z axis is also shown, I will have to modify it by changing into a clamp where the snout of the die grinder locates.
I also drilled and tapped the z rails. The alloy part (not shown) that the rails mount to is not thick enough to support bolts coming in from either side so I have made it so that the bolts come from one rail, pass through the alloy and screw into the rail on the other side. I used an end mill to cut a recess for the head of the unbreako bolts.
I drilled the y axis rails today and did a trial fitment to the plate. I was machining recesses for the heads of the bolts such that they sit inside of the circumfrence of the rail and the end mill went blunt, a combination of too high rpm and the hard chrome surface. I didn't have a spare handy and all the industrial suppliers are still closed for xmas so I just used a 9mm drill and didn't drill too deeply, I'll rebore them when I can get hold of an end mill.
I measured the width variation of the upper and lower rails on the y plate with a digital vernier and was pretty happy with the results. The total variation was 0.05mm, the lower limits were of course at the bolt points and the upper limits were mid way between the bolts. I should be able to get the lower limits more uniform by adjusting the bolt torques, that was the reason i designed it so the rail will not bottom out in the channel. When the skate bearings (being set to match the lower limits) pass over the sections mid point between the bolts the rails should squeaze down and closely match the lower limits so the overall variation should be minimal.
I need to buy some bolts long enough to mount the z axis rails before i can check the variation on them, I'll be doing that shortly.
Some more detail of the Rutex system.
The wiring on the power terminal: the blue wire (which should be fused) runs to the power supply positive terminal, brown to the power supply negitive terminal, black and white to the motor terminals, polarity dose not matter on the motor terminals as that can be changed with the tuning software.
The red cable is rj45 network cable which runs to the single ended line driver (which is wired to the encoder). The 15 pin connector is used to power 2 circuits on the motherboard and to close 2 circuits (e stop and out1/spi) to allow the tuning to take place. The printer cable runs to the pc.
There are several different Rutex tuning software packages which essentially perform the same function, the grapical user interface is the main difference, this one is the r2xtunevb6 package.
This is the graph which the tuning software produces, the instructions shows an ideal graph and the objective is to adjust the parameters to get your graph to look similar to the ideal graph. The motor can jump around and oscilate violently depending on the parameters, I would tune with the motors disconnected from the leadscrews to avoid possible damage, there are some notes on safety when tuning in the instructions.
Hi guys,
I'm back again after a few days holiday. I machined the bearing mounts for the x axis today. I made a jig to mount the blocks to so they could be machined as a set. Doing it this way is more accurite than mounting them in a vice as they can move too easily when tightening the vice.
The first picture shows the blocks mounted to the jig with the jig bolted to the table and the head tilted on a 45 degree angle to cut the faces of the mounts.
The second image shows an edge finder in use. For those who are not familiar with edge finders they are a probe like device with a spring loaded ball on the end, you slowly move the table intil the ball touches the surface of the job and the electrical circuit is closed which makes a red light come on and a buzzing noise. When it is at the point where the slightest movement can make or break the circuit you set the DRO to either + or - 5mm (half the diameter of the ball) depending on the direction the table is moving and you have your edge point. After that remove the edge finder and put in the cutting tool and start machining.
The last image shows the finished bearing mounts for the x axis which will run on 1" diameter shafts. Behind the bearing mounts is the jig (upside down).
I didn't have a very productive day today, I got bogged down with some other stuff but I did manage to get the y bearing blocks made and did a trial fitment. I tightened the angle brackets flush to the edge of the backing plate and bolted on the bearing mounts and put in the y plate, with a slight spring tension as the rails passed throught the bearings the motion was smooth and completely free of play, perfect. Here is an end view and back view of the y axis.
I mounted the rails of the z axis and did a width variation check today. There was .09mm variaton across the rails showing it to be unparalel so I disassembled it and wrapped a sheet of emery paper around one of the rails and rubbed the high points and got it down to a very respectable .02mm variation, the narrow sections were at the bolt points and the wide sections were mid way between, as expected.
I machined the z axis bearing mounts. The first image shows setting up prior to machining, I mount the parralels to the side of the table and then pull the job back against the spacer bar and torque the jig bolts, that way is is true to the table.
The next two piccies are of the router. We've been getting a few visitors and trying to explain what I'm building is difficult so I pinned up a couple of pictures on the wall. The final job will have 4 1" by 2" rectangular tubes running across the frame to support the mdf table top.
I tried to mount the z axis and the rails were slightly too wide for the bearings, I'm not sure what went wrong but some elongated holes in the angle plate sorted it out. Moving the z up and down its travel I noticed a very slight bump which turned out to be a tiny dint in the surface of the rail right where the bearing runs. I dont think it will be a major issue but the rail can be easily replaced if required.
Another update (just for you Rod ;-) ),
I modified the bottom plate on the z to take the router and made a bearing housing for the leadscrew which also ties into the main member to control the hinging effect which will be generated as the gantry moves on the x axis.
The four rings are adaptor plates for the servo motors so the side loads produced by the belt tension acts on the boss on the servo motors rather than the tiny mounting bolts. I will only be using three motors on the router initially but 4th and 5th axies are on my list of things to do at a later point in time.
The two rectangular bearing mounts in the side view image are for the y leadscrew. The "top hat" bearing housing is for the z leadscrew.
Rather than machine the ends of the ballscrews to take the pulleys I intend machining adaptors which will mount to the ends of the leadscrews and the pass through the bearing housings then the pulleys and then have a threaded section for a nut, that way if there are any machining errors on the adaptor it's no big deal, a replacement can be easily made rather than an expensive replacement of the ballscrew.
Cheers
Splint
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