Milwaukee Makerspace has a lot of equipment, and sometimes we get things that don’t quite work, and we try hard to get them working. We often succeed, but sometimes we decide it’s better to move on…
With that said, we’re looking to sell our Matsuura RA1F Vertical Machining Center, which is known as the “Red Dragon”.
It’s not currently running, but it was working months ago. Ultimately we decided that it would take too much work to get it into good shape for a makerspace, so selling it off as a whole, or in parts, will help fund a new CNC milling machine which is smaller and more suited to our needs.
If you’ve never used a VMC this probably isn’t for you, but if you really want a challenge, or want it for parts (and there are some very expensive parts in it) you might get a nice deal. Maybe you’ve already got one and need spare components? Perfect!
Before #2: My front door, in need of paint, some aesthetic happiness, a fixed doorhandle, and summer. My desire to add a little decoration to the door is, in part, what led me to the Makerspace. I had an idea for panels to go on either side of the door, but no equipment for making what was in my head. When I saw that the Makerspace had cnc routers…
IN THE MIDDLE
I took photos of leaves from the oak tree in our yard:
I traced the leaves in Illustrator, and — by looking at the structure of the tree — made my initial design. I exported the file into svg (with hints from Shane), and Ed helped me use Cambam to convert the svg file into the gcode that the Mogul desires.
After generating the gcode, we cut the first panel. For me, watching the cutting was like Christmas: exciting — while for Ed, stepping me through the process, this must have been like a long slooooooooow Christmas, watching the design appear through the three passes the router bit made to cut each (complicated) path. (In truth, Ed’s patience and help were the real Christmas present for me.)
This panel was an experiment for me, to learn about how thin and delicate the connecting pieces could be in such cutting. And I learned: what you cannot see in the picture above is how two of the leaves broke off quickly.
In the next Illustrator file I made (which I then cut on the Mogul with Steve Pilon’s also very generous and patient help), the leaves overlap and made their stems thicker. You might be able to see this in the final picture below, which shows the panels painted and mounted. Merry Christmas!
32V Power supply for Y axis motor. No regulation necessary!
Smoothieboard is supposed to read the config.txt file from its uSD card (conveniently accessible via USB) every time it boots. That makes changing configuration very easy and fast – all you do is edit the config.txt file, save it , and reboot the board. Firmware is updated the same way. With the ATMega2560 you have to find the configuration variables by searching through multiple configuration files, make the necessary changes, recompile the firmware, then flash the controller. I said the SmoothieBoard is supposed to read the file every time it boots, but it wasn’t doing it. I’d make changes and they would not appear in the behavior of the printer. Hmmmm.
Layers kept shifting in the X-axis- I expected Y-axis problems, but not X!
I attempted some prints and managed to get two decent ones in about a week of screwing around with it. I tried dozens of combinations of speed, acceleration, junction deviation (smoothie-speak for jerk) and even tried different slicers. The machine went completely nuts on two occasions and ignored the Z-axis limit switch and slammed the extruder into the print bed, gouging through the Kapton tape and into the aluminum! I decided I needed some professional help so I got on the #smoothieware IRC channel and discovered that the developers of the board/firmware hang out there quite a lot. After a lot of back and forth Q and A and testing someone suggested it might be the uSD card causing the problem. I picked up a new card at Walmart, put the firmware and config files on it , booted the machine, and attempted a print. PERFECT!
The new uSD card worked! The small round post is 4mm diameter.
I have made several prints since last night and they have all come out fine. I still have a little tweaking to do and to test the limits of the machine’s performance, but I think the problems are behind me.
Next up: X-axis redesign/build. I’m replacing the two guide rails with a single linear guide. I have also ordered and received a BullDog XL extruder to replace the hacked up QUBD unit I’ve been using. I’ll be adding a DSP driver and 32V power supply for the X-axis motor, too.
After that, I have some ideas for a filament respooling machine and ways to fix the retraction problem in the SnakeBite extruder.
I installed the Y-axis screw drive in MegaMax using the old NEMA-23 stepper motor. A couple really good things came from this:
1) I can now adjust the bed leveling screws from the underside of the bed using thumbwheels instead of a screw driver. I know, I know, everyone else in the world has been able to do this from day 1…
Thumb screw for leveling print bed. Screw is threaded into teflon block.
2) Unlike everyone else in the world, with fully supported linear guide rails, the print bed does not move in any direction but along the Y axis. In the old scheme, with the end-supported round guide rails, the rails would flex and the bed would move up and down when applying pressure to it (sometimes even the screw driver pressure to adjust the bed leveling screws). Now, if the bed moves at all in the vertical direction it’s because the bed plate (1/4″ aluminum) itself is flexing!
A couple bad things were also discovered:
1) The vibration and noise problem I was hoping to solve has not been solved. It has been made worse, though the character of the noise is improved to musical tones instead of just harsh buzzing and rattling.
2) Several failed test prints at ever decreasing jerk, acceleration, and speed settings have demonstrated that the old motor simply doesn’t have enough torque to drive the screw reliably at reasonable printing speeds.
Shift occurred in Y-axis due to insufficient motor torque.
Further research into the first problem indicates that the vibration and noise are inherent in using steppers, and worse in MegaMax than in machines that use NEMA-17 motors because of the higher detent torque in the NEMA-23 size motors. Detent torque is the little bump-bump you feel when you turn the motor shaft by hand. The solution to the problem is to use a good driver for the motor and a higher voltage power supply. The little A4988 chips in the Pololu drivers on the RAMPS board are very unintelligent- all they do is provide microstepping. They work OK for NEMA-17 size motors because of the speeds and low detent torques in those motors. When used with NEMA-23 motors the driver limitations become apparent – as they have in MegaMax- lots of noise and vibration.
Good stepper drivers are DSP based and automatically sense resonance and damp it electronically. They use phase controlled sine wave currents to drive the motors smoothly. Fortunately, DSP stepper drivers for NEMA-23 size motors are pretty cheap. Here’s video of the DM542a driver pushing a NEMA-23 motor around. I have ordered a DM542a driver.
The best power supply for stepper drivers is not a switcher, and running steppers from a switching supply will often result in a dead power supply. I will be building a simple, unregulated transformer, rectifier, and filter cap supply to go with the new driver.
Next came the question of how to determine how much torque is needed to properly drive the Y-axis. A bit of research took me here: Motor size calculator. You just select the scheme for which you want to size the motor, enter the appropriate data, and it magically tells you how much torque you need to do the job. When I ran the numbers on MegaMax, it told me that I need about 350 oz-in of torque (about double the torque of the motor I have). I did a quick search and found a Chinese made (of course) 425 oz-in motor for $50. Also on order…
The motor mount I am using is designed for a NEMA-34 size motor with which I use an adapter plate to allow the NEMA-23 motor to fit. Since I’m buying a new motor anyway, why not just get a NEMA-34 motor? It turns out that the best stepper for the job is generally the smallest motor that can provide the necessary torque. A NEMA-34 motor could provide much more torque but the detent torque and rotor inertia would work against smooth and fast operation, and require a bigger power supply.
Back side of MegaMax showing motor mount, adapter plate, flexible coupler, and drive screw in Y-axis.
The ATmega2560 and RAMPS boards will be replaced by a SmoothieBoard. It has a much faster processor, much better connections for motors/external drivers, etc. It currently lacks an easy way to add an LCD controller, so I may have to connect to a computer to start prints up (it has ethernet and a built in web server so it can be accessed from any computer on the network). When a clean way to add an LCD controller becomes available, I’ll add it. SmoothieBoard review
MegaMax has been and continues to be my main project for the last 2+ years. I am currently working on some upgrades that will make him more Mega and even more Max. The Y axis is being converted from belt drive to screw drive and the round guide rails are being replaced with linear guides and bearing blocks. The X-axis will also get converted to linear guide and bearing block and change from 5mm pitch belt to 2 mm pitch belt drive. I feel confident saying that once these modifications are complete the flaws/errors in prints will be due primarily to the nature of liquid plastic squirting through a nozzle, not positioning system errors.
I recently updated my web site with a sort of historical look at the project, including all the mistakes I’ve made along the way and the often failed attempts at correcting them. Here is the page that shows how it all started, how it has ended up, and where it is going. http://mark.rehorst.com/MegaMax_3D_Printer/index.html
As part of my effort to reduce the noise and vibration in the Y axis, I am going to try using a screw drive instead of the 5mm pitch belt. I rescued a screw drive assembly from a big XY table but it uses a 200W servomotor for which I have neither power supply nor drive electronics. Never fear! The motor was a NEMA-34 size, so I designed an adapter to mount the NEMA-23 stepper that MegaMax uses in the NEMA-34 motor mount. Next I needed a shaft coupler- the screw has a 9mm diameter attachment and the NEMA-23 motor has a 1/4″ shaft.
Adapter plate on NEMA-23 motor
I used DesignSpark Mechanical to design the motor mount adapter and flexible shaft coupler. I uploaded the motor adapter to Thingiverse (http://www.thingiverse.com/thing:526424) and it proved surprisingly popular so I designed another that adapts a NEMA-23 mount for a NEMA-17 motor (http://www.thingiverse.com/thing:526443). I had to make two attempts at the flexible shaft coupler- the first design proved a little too springy and flexible, so I tried again with a more beefy design. It turns out it is pretty easy to design this sort of thing in DSM. I probably spent 30 minutes on the first one and about 10 minutes on the second one.
I sliced in Cura because Slic3r was having some problems. The prints look a little rough because of all the support material required to print the springs, but they work fine.
Flexible shaft couplers- not-so-springy and super-springy.
Adapter and shaft coupler on motor
Motor mounted on screw assembly
I’ll post an update when I get the screw mounted on the machine.
A few weeks ago Mike Stone of CNCMogul.com visited the Milwaukee Makerspace.
Mike donated one of his machines to the space for testing and feedback as well as to use for the membership. It should also be mentioned that Mike is local and has his shop and distribution in Wales, Wisconsin.
Joe Rodriguez built one machine and I also put one together at our shop at home. So here are some thoughts on the process as well as some pictures. It isn’t a review as these machines haven’t really been put to the test as of yet. Time will tell.
The CNC Mogul is a general purpose 3 axis CNC kit that is relatively easy to put together and can be used for anything that you like. I’ll be using ours for routing and Joe wants to make a CNC plasma cutter with the one in the space. The basic kit is affordable and it uses the Makerslide as it’s building blocks. The stepper motors are run with a rack and pinion setup on aluminum tracks and gearing as well.
The controller is a Chinese Tb6560 Stepper Motor Driver Controller that is controlled via parallel port.
The power supply is a 24V 14.6 AMP 350W Max Power Supply.
The whole kit can be ordered online from 2ft X 3ft up to 4ft X 8ft. Custom dimensions are also available.
So here is the kit before assembly. This is a 3ft x 3ft kit that I will be building and using with a router.
This is the kit right before opening.
Inside the kit there are a bunch of baggies with tons of little parts. You can look at the manual here
I’m assembling the quad rail kit. Once I start pulling things out of the box there is an amazing array of parts that explodes out of it. Fortunately each bag and part are well marked.
Everything that you need to build your own CNC controlled machine.
Everything is labeled really well.
Everything is labeled really well.
The kit took approximately 3+ hours to put together. The documentation in the manual is hit or miss. The pictures are extremely good and really help in putting this together. The accompanying text is also great for the first 1/3 of the manual and then you’re left to interpret pictures from there. There are a few questions that came up while building this but fortunately I was able to figure it out.
Little by little the parts are being built.
After the gantry gets built and all of the wires are connected it’s time to test. CNC Mogul recommends using Mach 3 for your machine control. And even has a few pointers on how to setup Mach 3 on their site.
I decided to go with LinuxCNC because it’s open source, I’m comfortable with Linux and it’s low cost (free). I loaded it up on a spare computer and after running through the instructions I was able to control the stepper motors on the Mogul.
What I had difficulty with is that the CNC Mogul uses an “A” axis and “Y” axis slaved together. LinuxCNC can do that but you can NOT test for that in the setting up process. You essentially tell the “A” axis to use the same step and direction pulses as the “Y” axis. I also inverted the “A” axis so they would turn the same direction when they are facing each other.
One of the other difficulties I had was figuring out the leadscrew pitch to enter into LinuxCNC. After some experimentation 1.27 inches per revolution seems about right but some more testing is needed.
Once you’re finished building the whole thing you need to mount it to something. I picked up a Craigslist find and the Mogul fit perfectly.
Silversark put together an amazing fashion show on Friday to showcase pieces she made inspired by church architecture and her trip to the Netherlands. This is something I cooked up for a background piece for the show.
The design work took several months and the actual creation of the piece took about a week, working 12-16 hours a day. The frame is made from CNC routed aspen (thanks, Jason H.!) which is a rather “fuzzy” wood and required two days to hand finish, including the use of a set of needles files to smooth out the inset edges.
The acrylic panels were hand-stained with Gallery Glass stain and simulated liquid leading. They’re not quite finished yet, but I plan to complete the staining within the next week.
Recently, I’ve been doing some work sandblasting. Because Pi Day was coming up (March 14 – 3.14), and I just happened to have a stack of Pyrex pie pans handy, I thought I’d go ahead and try making my own custom Pi Pans.
I started by designing a logo in Illustrator. Well, that’s not quite right. I actually did an image search for “Pi”, saved a .bmp, and then TRACED it in Illustrator. Once in vector format, the image can be re-sized and have the stroke and fill colors changed, all non-destructively. When I was happy with the logo, I printed one out on plain paper. Then, I cut it out and taped it to the back of a pie pan. This gave me a real-world mock-up to make sure I liked what I had BEFORE going through the trouble of making a vinyl stencil and sandblasting.
Next, I exported my image as a .DXF file, and then opened it in Silhouette Studio, the software that runs the CNC vinyl cutter machine. In studio, I made sure the image was still scaled correctly, then positioned it where I wanted it on the 12″x12″ cutting area. The last thing I did before cutting was to FLIP the image. Since I would be sandblasting on the BACK of a glass pie pan, the image needs to be flipped so it is viewed correctly from the front.
The Silhouette Cameo cutter cuts out the pattern quickly and automatically, taking about a minute for the whole process.
I removed the vinyl, and cut it into quarters, as I was able to fit four stencils on a single page. I then peeled away the “Pi” logo, leaving the vinyl around it. This is because I am making a stencil. I want the sandblaster to hit the glass where the vinyl does NOT protect it. This will etch the shape of Pi and leave the glass around it clear.
I used transfer tape to place the Pi logo stencil on the back of the pie pan, and then removed the transfer tape. Next, I covered the rest of the back of the glass with regular masking tape. At this point, the pie pan is ready for sandblasting.
I put the pan into the blast cabinet and set the pressure regulator to about 70 PSI. Anywhere from 60-80 works pretty well. Higher pressure than that can start to cut into the vinyl. I simply held the pie pan in one hand and pointed the sandblaster gun at it with the other. It’s much like spray painting – just pull the trigger and try to give a nice even coat.
Once done sandblasting, I pulled the pan out of the cabinet and peeled away all the masking. Next, I washed it with soap and water in the utility tub and then dried it.
The finished effect turned out pretty well. The Pi is a very prominent white frosted character on a clear background. Most people catch the visual pun of “Pi Plate” right away.
Besides the Pi Plate, I also came up with “Apple Pi” and “Raspberry Pi” designs based on popular computer company logos. Both of those turned out very well.
By that time, I was starting to feel pretty confident in my stencil design and sandblasting skills, and I wanted to make a “Cherry Pi” logo, but realized that there is already a great pattern for that – the album art from Warrant’s 1990 album “Cherry Pie”.
I spend some time in the vector software painstakingly tracing the artwork into a simplified vector. Next, I made a cutting from vinyl. All of the fine lines were tricky to peel off with a pair of Xacto knives. Once I finally had the finished stencil applied to another pie pan, it was time to sandblast.
After that, I simply peeled off the masking to reveal my WARRANT CHERRY PIE pan. My wife’s birthday happens to be March 14th – Pi Day. She’s a fan of late 80’s/early 90’s rock, so gave her the CHERRY PIE pan (with a home-baked cherry pie in it) as a Pi Day/Birthday gift. She got a kick out of it.
How about you? Have you ever personalized some glassware through etching? A “Please return this pan to….” etching sounds like a good idea for pot-lucks! If you have done some etching, post a photo or link! Otherwise, send your ideas for other cool glass etching on up cycled kitchen-ware!
With a lot of hard work from Ed H. and Steve P. our 4′ x 8′ CNC router has achieved a milestone, instead of the X axis sitting on the ground it has taken a leap up and is now mounted, ready for the Y and Z axis to be mounted to it along with the electronics and motion control.
The X-axis is ready to be milled here.
Join us for The Greatest Show (& Tell) on Earth at Wisconsin State Faire Park September 24th & 25th, 2016. Admission is free. A joint presentation by Milwaukee Makerspace and the Betty Brinn Children's Museum.
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