Author Topic: CNC Router Built in the Workshop  (Read 605 times)

Offline Bruce W-S

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CNC Router Built in the Workshop
« on: December 22, 2018, 07:23:55 AM »
CNC Router

I found making small complex parts for engine models time consuming and decided to build a CNC router to do the task. The specification was that it had to have the capability to cut up to 6mm steel, brass and aluminum plus other similar materials.

The electronics is quite straightforward and there have been plenty of articles describing their construction. In my case, I scrounged the computer with required XP operating system (Windows 7 is acceptable) as well as most of the material. The controlling software is Mach 3 “mill”

The construction used 20mm thick aluminum plate, which was suitability, machined and bolted together. The construction may seem to be somewhat over the top however, I had the opportunity to get a friends machine up and running and noted the vibration when cutting aluminum plate. So I decided that building the machine as ridged as possible was the way to go. A lot of routers have been successfully built however, this was my solution. The spindle is 1.5 HP using a single phase to three-phase controller. The spindle is also water-cooled which has worked well as the motor has never become hot even after several hours of machining. I was given a forth axis device which included a chuck but to date I haven’t used it.

Since building this machine, I have converted a lathe to CNC for a friend. The only complexity was the motor speed control and the programming for the tool turret. However, it all worked in the end. I am just in the process of building the controller to convert a mill to CNC for the same person.

My router is in constant use for all manor of tasks and it makes a useful addition to the workshop. If anyone would like more detail on the build, I am happy to provide it (or on any other CNC problem).  Note, I use Cambam to convert the DFX file to G code. Requires understanding the basics but there is plenty of help.

Also, I have now mounted the computer screen on a hinged mount so that the unit is totally self-contained on a movable trolly. I have a small workshop so everything that can be mounted on wheels is and moved out when required.

Bruce

I have included the following photos:


Photos 1 and 2 show the general arrangement of the router.

Photo 3 shows the machine with the water-cooling on while cutting some steel plate.

Photo 4 shows carbon fiber sheet that has been cut out for a mini quad copter (things you do for people)

Photo 5 shows some flanges being cut out from 6 mm brass for a marine engine.

Photo 6 some engine components being cut out from 5mm sheet steel

Offline Fowellbox

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Re: CNC Router Built in the Workshop
« Reply #1 on: December 22, 2018, 08:16:42 AM »
Hello Bruce, what a wonderful project. I, for one, would like to see more details.
Brian

Offline Roger B

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Re: CNC Router Built in the Workshop
« Reply #2 on: December 22, 2018, 10:35:08 AM »
That's a fine machine  :praise2: How many cuts do you have to take for those 5mm steel pieces or will it do it in one bite?
Best regards

Roger

Offline yogi

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Re: CNC Router Built in the Workshop
« Reply #3 on: December 22, 2018, 02:12:41 PM »
I like it!  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Definitely sturdier than the average router you see out there. Any chance of a video to see it cut?

Offline Steve17

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Re: CNC Router Built in the Workshop
« Reply #4 on: December 22, 2018, 04:52:19 PM »
Hi Bruce, what a nice sturdy looking design. I can't recall ever seeing a home made gantry design cutting what looks like steel before. How slow can you make the water cooled spindle go?
Steve.

Offline mikemill

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Re: CNC Router Built in the Workshop
« Reply #5 on: December 22, 2018, 05:03:20 PM »
Bruce

That's a very well built machine, like all mills rigidity is very important for it to work well. I bought an X3 CNC mill around seven years ago and without doubt it is the best machine tool I ever invested in.
The scope of these tools is immense giving you the opportunity to create complex parts, I hope you will get as much enjoyment using the mill as I do
mine

Seasons Greetings

Mike

Offline Bruce W-S

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Re: CNC Router Built in the Workshop
« Reply #6 on: December 23, 2018, 03:57:36 AM »
Roger and others

I will try to answer your questions as best as I can.  When I first built the machine, I did a test on aluminium and steel 6mm. I found that providing the feed rate was modest it cut just fine. Note, I just cut a straight line for the test. However (there is always a however) in practice this was not the best strategy. I had a learning curve re suitable cutters and I use a maximum of 6mm. Basically not all cutters are suitable. The next issue is in machining a complex shape, sooner or latter you will be climb cutting which you have to allow for. I am certain that there are people out there who could offer far better advice on cutting methods however this is my experience in isolation. Cutting steel which is the most difficult, I use a twin flute carbide cutter and for five mm steel (the most common for me) I make three 1.25 mm deep roughing cuts with 0.2mm clearance. The final cut (on line) of 1.25 also cleans up the the overall piece. The ability to do rough cutting followed by a finishing cut is a feature of Cambam. I am sure other software will do the same. The time taken to do four cuts is about the same as doing it in one cut.

The other issue, is securing the work piece. If making a deep cut and the work piece moves by the smallest amount it is bin material. Straight lines are easy, it is the curves that put the load on the machine and in particular the cutting bit. If the cutting rate on a curve is too great, the cutter snaps, the machine does not slow down. I have a number of broken cutters as a result of my learning. If I have the time, I will change the bed from aluminium to steel making the T slots out of bright flat bar. The aluminium seemed like a good idea at the time as it had the T slots incorporated however. I don't think that you get the same purchase as with steel just my thoughts.

 Aluminium cutting is easier especially if you use a single flute carbide cutter however, I still do a minimum of two cuts to improve the final finish. I was asked to repair two model railway carriages (about one meter long) and it required making new sides which I cut out on the router which included all of the windows and doors etc. I then changed the G code from cutting internal to the line to cutting external to the line. The end result, all of the windows just pressed in exactly. I could never have achieved that doing it manually.

The spindle I use (which was given to me) is good for 1.5 hp and is three phase via a single to three phase converter. These converters have a speed control to adjust the frequency and thus the speed of the spindle. The spindle is designed to run at a maximum of 400Hz and they are two pole motors. Their upper speed is  24,000 rpm and in theory should run down to about 50Hz or 3000 rpm but you need to be careful of the heat. Water cooling is a benefit here. I run my spindle between 3 and 8 thousand rpm. This requires some changes to the controller settings to ensure the power curve remains constant. Basically as the frequency is reduced, so is the voltage so if the settings are not changed, at 200 HZ you have half power and at 100 Hz you have quarter power (approximately).

The higher cutting speeds require plenty of coolant and I use a coolant mixed in with compressed air which is used to remove the cuttings. If anyone is interested in more detail of the build etc send a personal email.

As for video of the machine working, I as yet haven't made one. I have made then of some of my engines but have found the files so large you can't up load them to these forums.

All the best for the festive season.

Bruce