Buildlog Title: Big Ol' CNC, by Awesomenesser

Builder: awesomenesser

Member Since: 2011-03-02

Saturday, August 25th 2012 - 6:44 AM

I figured I should start up a buildlog for my most recent project. I recently acquired a used chinese cnc table router from my work. (it is basically the same unit that automation technologies sells) I saw it in the back one day marked "For Disposal" and offered to take it off their hands. The unit was in pretty rough condition, and was missing motors and drivers. They removed the spindles and used them for custom pick and place machines to assemble/waterproof our products. Since this was their first/prototype machine it was pretty much covered in half hardened epoxy and had a lot of modifications and parts missing.

: Initial condition...

After spending a couple weeks going through countless paint scrapers, shop cloths, and acetone I managed to get all the epoxy off of the table (and the t slots). I also removed the stock rubber sheets that come pre-attached to the cnc, not really sure why you would want this material but I guess it is a kind of sacrificial layer (even though it is glued on and isn't replaceable). I also don't really understand why they painted the aluminum table surface in the first place.

: Table surface before cleanup.

I don't plan on repainting the table surface, but I am going to give the stand a nice coat of black after I get it cleaned up.

: The clean table surface.

: CNC on my fancy rolling cart.

Luckily my work happened to keep the spindles and vfd drives for the machines which will save me a lot of money. Luckily the unit also shipped with a 110V to 220V transformer because the vfd drive requires 220V. I do still need to source some stepper motors and stepper drivers. I plan on using either Gecko G201X's or G251X's depending on my motor rating. I cant decide if I should get the 3.5A 280oz-in motors or the 5A 400oz-in motors. I have already purchased a 48V 10A power supply which should be sufficient but might be cutting it close.

: Driving the spindle at 400hz.

: My power supplies and din distribution blocks. (220VAC 110VAC 48VDC 12DC)

As for control I plan on using Mach3 (already own it because of my laser cutter) and because I am out of fast computers with parallel ports I will most likely get a USB controller like the KFLOP (and not a smoothstepper thanks macona). I already bought another cable track for the X gantry, but I still need to buy everything to build the spindle liquid cooling system.

I still have a decent amount of work to do to get this thing up and running but hopefully I should have it going in a couple more weeks. As an update my laser has been doing great my tube just passed its first birthday so hopefully I can get another year out of it. I am looking forward to being able to cut things other than acrylic, but I still love the laser for its ease of use and cut quality. As for my hadron I still havent finished wiring it up been really lazy recently but I did preorder the Azteeg X3 and couldn't resist his heated platform so if anyone wants to buy my never used (or even soldered too) Ultimachine Prusa heated bed let me know.

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Saturday, August 25th 2012 - 6:44 AM

Post reserved for future pictures and videos...

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Comment from: macona on Saturday, August 25th 2012 - 9:05 AM

You might look at the kflop from Dynomotion. It is a much more capable controller than the smoothstepper. I had a smoothstepper on my mill for a while and went back to the parallel port with all the issues. Once I get working again I am going to get a kflop for my mill. A friend of mine got one for an X/Y stage and they work very smooth. You can use them with their own free CNC software or a plug in for mach 3.

http://dynomotion.com/KFLOP.html

Saturday, August 25th 2012 - 1:25 PM

macona wrote:You might look at the kflop from Dynomotion. It is a much more capable controller than the smoothstepper. I had a smoothstepper on my mill for a while and went back to the parallel port with all the issues. Once I get working again I am going to get a kflop for my mill. A friend of mine got one for an X/Y stage and they work very smooth. You can use them with their own free CNC software or a plug in for mach 3.

http://dynomotion.com/KFLOP.html

Thanks for letting me know the KFLOP exists, I need to do a little more research, but I will probably end up buying one.

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Comment from: macona on Sunday, August 26th 2012 - 8:48 AM

They have gotten pretty good reviews on CNCzone. Many people just use the included software. I want one so I can do rigid tapping on my mill. Right now I have to program the tap cycle by hand which could be pretty easy to screw up.

Comment from: Liberty4Ever on Monday, August 27th 2012 - 5:04 AM

I'm currently working on my very first LinuxCNC conversion. It's a bigger older CNC! It's a gantry machine like the one you're converting, but it has a 7.5 HP radial saw, two 15 HP routers and two air drills. The bed easily accepts 1" thick sheets of 4'X8' MDF. I call it The Beast. Most of the I/O wiring is done. I should be moving the Z axis this week and X, Y and A axes next week. Once I finish this project for a friend, I'll get back to my two Hadron ORD Bots and my own 10"X24" Clausing lathe LinuxCNC conversion. Then I'm gonna build a laser!

Good luck with that CNC router conversion! Neat project!

Comment from: TLHarrell on Monday, August 27th 2012 - 4:58 PM

Awesome. I've been looking for a CNC controller that will do standalone G-code interpretation. This looks like it'll do the deed.

Friday, September 14th 2012 - 1:09 AM

I have made a little progress over the past weeks. I was able to strip the entire frame down and repaint it and mount some of the initial wiring.

: Painted frame and cart.

: Main electrical distribution.

I also received my motors and a gecko drive (I'm waiting until I buy the other two). I ended up going with the 400oz-in motors so I went with the G201X drive which I will be running at 48V/5A. I decided to use the laser cutter to make an adapter plate to mount the heatsink to some fans, this should be more than enough to cool the drives.

: Gecko drive heatsink unit.

: This should be enough.

I should have the chance to mount the rest of the electronics in the cabinet this weekend then I get to start wiring.

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Comment from: Liberty4Ever on Friday, September 14th 2012 - 1:52 PM

That's looking really good. I'm looking forward to seeing your project coming together.

I've been busy. I should take a little bit of time and upload some pictures and descriptions of my project. You've inspired me!

Sunday, September 30th 2012 - 3:36 PM

Ok, so the main purpose I am building this cnc is to cut things that I can't do on my laser. I really want to be able to do a good job cutting aluminum but I know I would probably have issues with cutting aluminum with my 1.5kW 24000rpm Chinese spindle. So I started looking into ways to make this possible and decided I should implement some kind of lubrication system. I stated looking into how to do this and think I have everything figured out except for what fluid I should use. I have read that aluminum doesn’t really need the coolant part as much as the lubrication part but I don't think I could afford to use a fluid that isn't in concentration. I looked around and found one Mobilcut 102 which says it is great for cutting aluminum and has additives to reduce bacteria/foam/odor rust protection. It says it gets diluted at a ratio of 1:30 which can be varied depending on material, and McMaster (2507k18) sells a gallon of the concentrate for about $30.

I really just wanted to see if anybody else has any recommendations on what cutting fluid I should use. Also do you guys think I will have issues cutting aluminum with my setup, I have a 6mm, 1/8", and a 1/4" collet so I will be restricted to small end mills. I think the flood system will help out a lot (at least hopefully more than the mess it is going to create).

In order to accomplish this that I will be adding gutters to the two short sides and adding sidewalls to the two long sides (parallel to the tables tslots). I still need to find a filter for the filtration system but once I get the fluid I can do some tests (I like the reusable coffee filters but they might not have high enough of a flow rate). I already found a nice pump that does about 1.2 gal per minute and I rigged up electronic speed control so I can very the flow rate. I will be using a 5 gal bucket mounted on a drawer system in the back of my cabinet for the reservoir. I figure I need a very large bucket because of the amount of table this 2ft x 3ft table will be able to hold before it starts recirculating. As for the nozzle I bought a set of 1/4" loc-line flexible hose. Unrelated I bought another loc-line hose for a compressed air output for when I am cutting wood. I will post pictures of the setup when I get everything fabricated next weekend (I am waiting for my aluminum to arrive).

On another note I finished the wiring this weekend (at least the electronics cabinet wiring) so that means I will get to install the table surface soon and start working on upper gantry stuff. Here are a couple pictures of my progress.

: The wired electronics cabinet.

: The line level distribution system. (I should really paint that transformer box black)

: I cut out half of the back panel to mount my flood coolant drawer. Luckily the Chinese just tacked it on.

I guess I had one other quick question how much cooling do these Chinese spindles need? I was thinking of installing a dual 120mm radiator and pump loop, is that too much or too little?

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Comment from: mikegrundvig on Sunday, September 30th 2012 - 3:52 PM

I use SynCool to cut aluminum all day long and it works great. As for flow, that's tricky - one of the biggest issues you will have with that spindle is chip welding. This occurs when you can't clear the chips fast enough and things get hot. This also makes for a bad surface finish and kills the life of the end mills. Lots of people just use WD-40 to lubricate while cutting aluminum and compressed air to blow away chips. This works pretty well at slower cutting speeds. With my big mill, I use a cheap debris-capable sump pump from Harbor Freight in a 30 gallon Rubber Maid tote full of coolant. I then blow enough volume of coolant to remove the chips too. This keeps heat down to nothing, removes the chips, and gives me a good surface finish. One thing to note - it's going to spray coolant EVERYWHERE when it hits the end mill at high RPM. I had to build a full enclosure out of PVC and shower curtain. It's pretty ghetto but works great.

-Mike

Comment from: Liberty4Ever on Monday, October 1st 2012 - 2:29 AM

awesomenesser wrote:Also do you guys think I will have issues cutting aluminum with my setup?

If you stick to smaller end mills and your goal is mostly oriented toward cutouts and engraving in aluminum sheet, if you restrict your cutting to slow feed rates, I think you'll be fine. If you want to hog out big chips of aluminum and do some serious machining of billet aluminum, you'll want a Bridgeport style milling machine or a vertical machining center. I have an inexpensive Grizzly G1006 benchtop milling machine that's paid for itself five times on the little work I've done on it. Almost every time I use it, I think about converting it to CNC, but then I come to my senses and plan to sell it and buy a used Bridgeport clone and convert it to CNC. Actually, I saw a very nice conversion of the Grizzly (also offered under many other names). Not much of the original remained , but it became a mini vertical machining center, which would be difficult to accomplish with a Bridgeport knee mill. It was fully enclosed in a cubical shape, with an integrated flood coolant system. The iron is probably suitable for a 1 HP or 1.5 HP spindle. Mine shipped with a 2 HP spindle, which is probably over powered for the rigidity of the cast iron.

awesomenesser wrote:I think the flood system will help out a lot (at least hopefully more than the mess it is going to create).

I'm trying by best to avoid flood cooling. My shop is in the basement, and I don't want the house to smell like a machine shop, and most of that smell is the coolant. There are low odor coolants, but they still stink too much for a basement, IMO. If you're machining in your garage, that probably wouldn't be a problem. But you still have the problem of coolant flying everywhere. Shoot a stream of coolant at an end mill spinning at 10,000 RPM and see where it goes! If I was converting to flood cooling, I'd put the entire machine in a big box, and I'd probably interlock it so the spindle and flood coolant are disabled unless the door is closed. I'm planning on short run production on my lathe once I convert it to CNC, and I'll be turning steel parts, and I'm going to try to get by with compressed air for coolant and carbide tooling (that I expect to replace much more often because I'm running without coolant). We'll see. For occasional hobby use or even small scale manufacturing, I think conventional coolant systems are probably more trouble than they're worth.

awesomenesser wrote:Here are a couple pictures of my progress.

Totally awesomenesser! Very nice job. Much better than the original, I'm sure.

awesomenesser wrote:I guess I had one other quick question how much cooling do these Chinese spindles need? I was thinking of installing a dual 120mm radiator and pump loop, is that too much or too little?

I just designed the cooling system for my 80W laser tube, and the water cooled spindles and water cooled laser tubes typically use very similar setups. In the case of my laser tube, I guessed I'd need to remove 800W of heat. I used a 120mm X 240mm radiator. With a good fan, a 120mm X 120mm radiator would have probably worked. I think your spindle will have considerably less waste heat. Electric motors are much more efficient than laser tubes. You may only have 200W or 300W of waste heat. That's a complete guess. The manufacturer should provide that spec. But for hobby CNC machine conversion, most people don't go to great extents to quantify and calculate everything. It's more TLAR engineering (that looks about right). Err on the more cooling side and call it done.

I did notice that the little submersible pump shown in the Automation Technology video demonstrating the coolant setup on their comparable gantry router (from your earlier link) was tiny and pathetic compared to the manly coolant pump that I selected for my laser cooling. That small pump implies that not much cooling is needed. The delta T of the water is pretty much fixed by the room temperature on one end and the maximum motor temperature (or the boiling point of water!) on the other end, so the amount of cooling is purely a function of flow rate, assuming the radiator and cooling fan is large enough. That tiny pump isn't moving a lot of water, so it's not sinking a lot of heat. The 120mm radiator should be more than enough. BTW - If your muffin fan isn't pushing enough air through your radiator, you can always upgrade it in the same form factor. I went hog wild and bought a pair of the very nice looking fans from LightObject.com when I ordered the radiator. I checked after placing the order, and they were cheaper than the eBay prices for the same blower. That was true for a lot of LightObject components.

http://www.lightobject.com/Ultra-Strong-12cm-DC12V-Cooling-fan-200CFM-P605.aspx

In fact, you might benefit from browsing their entire selection of cooling components.

http://www.lightobject.com/Cooling-C52.aspx?s=OrderBy%20ASC&c=52&p=1

In addition to low prices and fast shipping, Marco was extremely pleasant. He's very customer oriented.

Water cooled lasers always use a flow switch to ensure that the coolant is actually flowing, as opposed to simply turning on the pump and hoping it's flowing. The laser power supply is not enabled if the water isn't flowing. I'd do the same thing for a water cooled spindle. I'd have the flow switch wired to an enable pin on the VFD. Barring that, I'd have the flow switch operate a relay that supplied power to the VFD that powers the spindle.

http://www.lightobject.com/Search.aspx?k=flow

As to your question about too much or too little cooling... for hobby CNC machines, I'm inclined to agree with Robert Smith's advice in a song by The Cure. "Too much is never enough."

Monday, October 1st 2012 - 3:48 AM

Liberty4Ever,

I went with a really nice pc liquid cooling system for the laser and paid a pretty good amount of money for it and I want to avoid that if possible. I like closed loop systems so I will be avoiding the submersible pumps and will go with some kind of inline pump, hopefully a cheap ebay rip off one and not the swiftech I have in my laser. I will probably get one of the new swiftech radiators with the reservoir build in, I just need to decide how large it should be.

I know the flood system is going to be a huge mess but since the table surface is 2'x3' and I will most likely be working with small pieces I will be able to setup some kind of shield to contain the liquid to the table itself (once it is going I will see what I can come up with). I have seen machines with plastic brushes or plastic sheet that hangs down around the mill bit to keep the liquid contained.

Bart, if you happen to read this what kind of cooling do you use on your spindle/what would you recommend?

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Comment from: Liberty4Ever on Monday, October 1st 2012 - 4:31 AM

awesomenesser wrote:I went with a really nice pc liquid cooling system for the laser and paid a pretty good amount of money for it and I want to avoid that if possible.

I paid about $100 for the entire cooling system for my laser project and that seemed reasonable and appropriate. I think it's gonna be vurra vurra nice. You could probably do very well with the same setup, but only one blower instead of two, and the 120mm X 120mm radiator instead of the 120mm X 240mm that I used, for around $70.

I'm all about doin' it on the cheap, and for one off projects, my favorite is lightly used high quality stuff on eBay for cheap, but reasonably priced new stuff of high quality is almost as nice. Including convenient one stop shopping instead of an eBay & Craig's List scavenger hunt to save $20, buying new looks like a pretty good idea... particularly when that time could be better spent designing or building, which I enjoy a lot more than shopping.

Friday, October 5th 2012 - 4:03 AM

I decided the light switch on the side looked pretty stupid so I decided to replace it with a AB disconnect switch. I found it on ebay for $14 so I couldn't pass it up. I also got my USB port installed. I found these waterproof twist connect cables and panel mounts on digikey. I didn't really need the waterproof feature of the twist lock will be very nice. Here is a link to the series info on the usb cables here digikey carries almost everything in this pdf.