BeTrue3D Printer build part 3 – Assembling everything (almost)
Time for a new blogpost on the build-process of the BeTrue3D Printer, since last.
I’ve kept my facebook users updated, via regular posts to my facebook page, but it has mostly been photos, while I’ll explain what has happened and talk about the decisions made in this post.
- Parts Used
- Z-stage parts
- Z-stage Gantry plate
- Building the BeTrue3D Printer
- Lots of extra alu-extrusions?
- Mounting electronics
- Extruder connector panel
- Front LCD planning
Lets start by looking at the status right now, and see if it matches my projected result.
I’d say it’s a success. Means I was either lucky my planning worked, or that I was thorough when doing my design and planning. I prefer to pick the last one.
I AM going to make a complete BOM (Bill Of Material). I had created a parts list, on my open builds page, but it disappeared since I worked in 2 tabs at the same time, which isn’t working for that site.
I am going to fill it in again when I find the time to do so 🙂
I did create a small youtube video when unpacking the big box of goodies from RobotDigg, where I bought most of the parts aside from alu-extrusions and metal rods.
Here you can see the incredible nice hollow Nema 17 motors along with the bespoke 1204 300mm ballscrews and BF10 part used to fixated the ballscrews in the top. I don’t need support block near the motor, as the shaft goes through the motor and is fixated in the bottom, as you can see from the images.
Z-stage Gantry plate.
This is one of the few custom items I’ve had made for this project. I simply just had no way of making this myself, but was lucky I found someone who could manufacture it for me.
I learned a lot doing this project. Not least that it’s important to mark it m3 and not ø3 when I wanted a hole with threadding. Meaning mark endresult and let the professional figure out the hole-size, unless you want to do the threadding yourself.
After recieving it, someone asked me if I wanted to use motor-alignment on z-axis! Uhh? I talked some to the maker of RepRapFirmware and was told he planned to add this in a later firmware version, so I decided I’d make mine compatible for such a day, which meant I had to make a hole for an additional long m3 screw to hit a second z-max limit switch to facility this motor-alignment thing.
I carefully measured up, used some painters tape, and then drilled a 2,5mm hole and then tapped m3 using my trusty Makita hand tool. First time I use powertool for this, so was pretty exciting. Remember to use some cutting-lubrication if you do this kind of thing 🙂
I had one last thing I needed modifying, as the hole for the ballsc were 21,5mm and the ballscrew actually ways 22mm, so had to enlarge it slightly.
You can see how it doesn’t fit in the hole. I carefully used my dremel and a small file. Was actually pretty easy to do 🙂
This is the second custom item for the BeTrue3D Printer build. I had a PEI-coated, black oxidized plate made with a “logo” lasered onto it by clever3d.de.
Note: Price is much higher as soon as you move away from natural color. Lasered logo is only like €3 though! He makes custom sizes at no extra charge, so it’s perfect for any printer project. He also offered to make the z-lift plate at a resonable price, which I would had taken if I hadn’t found one nearby who could do it for me, so this is a nice source for custom aluplate work.
It looks absolutely awesome! unfortunately the rear hole was not completely centered. My plate is 29cm long and the hole should be at 14,5cm, but was placed at 15cm. Guess the mechanic just had a 30cm plate in mind, when he ‘centered’ the hole.
While I was rather bummed by it, Frank from clever3d.de set right out and made me a new one without complaining, which is incoming now.
I did not have to return the faulty plate, as some shops insist on doing, which is a huge bother.
Building the BeTrue3D Printer
In my last blog post I talked a lot about dimensions and why I did what I did. One thing I didn’t talk much about was the reason for the 2 layers of alu-extrusion bars at either end, up top. I did it in order to maximize the XY plane, as the sliders can slide in over the mechanics of the Z-stage.
Doing it like this also ensured I had some flexibility on the placement of the bars fixing 16mm rods in place, without compromizing the rest of the structure, as these rods might vary a bit in length.
I have used 12mm rods for the X-axis to avoid any bending. I can bend the 8mm rods in my Ultimaker 2 machines using a finger deemed 8mm too small for longer runs. I couldn’t be sure about 10mm so went with 12mm.
I’ve used 2x SCS12UU with bushings for each side. They each have a selfgraphite block instead of ballbearings to reduce noise and to raise accuracy as well.
I’ve heard this quite a few times. And yes, you can say it is. I’ve done it for a reason though, which is an attempt at ensuring squareness and rigidity. I’ve had multiple checks build in, meaning if one thing doesn’t fit, it means something is wrong in a differnet place.. meant a lot of time putting it together, but also that I had some “early warnings” if I had done something wrong, and could fix.
If you are a professional mechanic with relevant skills, I’m sure all this precation is unnessary, but for me, as a novice-builder, it has proven quite usefull 🙂
Lots of extra alu-extrusions?
Even aside from the build in “fail-safes” I’ve added a lot of extra aluminium bars. To be more exact, I have 4 extra at the “floor” and 1 extra at the top almost- rear.
Alle these bars are put in place to mount panels and electronics on, and also to hide facility the wiring in an orderly fashion. I used the bars, as it was a cheap and easy way to do it since I was ordering a lot anyway.
I originally planned to have some acrylic plates lasercut, but I decided to cut some costs and make some myself. While browsing for material to use, I stumbled across some nice “hobby plate” made of 5mm thick white paper material. It’s pretty sturdy, but very easy to cut and much cheaper than anything else I looked at.
I didn’t use the ferrules that came with the board as I simply just couldn’t get them right.
I even bought a special tool for it, but didn’t get good results. I know ferrules are the professionals’ choice, but I just couldn’t get it to work.
I used some basic clamp on metal pieces instead. I really don’t know what they are named, but for the PSU end I used the O-ring style and straight pin for the terminal end on the electronics parts. I used some heatshrink on each end.
I did this using some basic tools. The crimp tool was bought in a local hardwareshop for $12 or so.
You can see the DC-AC Solid State Relay next to my PSU. I’m going to use this for my AC Silicone heater for the heated bed. I have a small fuse between the PSU and SSR in case something goes bad.
Next photo shows how I’ve mounted my 5 extruder-bar (albit mounted wrong here), and also done some of the back paneling, including power connector and off/on switch. It has build in fuses. AC earth is connected to the frame of the printer as well in case some short is happening.
Extruder connector panel
I rather don’t like hard-wiring my external components to internal parts, as it is really hard to remove or repair parts, so I set out to make a panel with connectors for each of the extruders.
You might spot I have moved up the extruder-bar. I had to do this, or the bowdne output would interfere with the belt running for the CoreXY mechanics. I had planned this, but didn’t look at my plans while executing.. that’ll teach me. Need to find a fitting piece of material for the gap now!
The connectors are 4-pin Mini-molex 3.0
In case you wondered what kind of extruders I’m using. I’m using Belted Extruder V3 1,75mm which I desinged myself.
I designed them after I tried a wealth of different extruders, but most required special parts, which only the designer sold, or other exotic hard to come by parts.
Every single extruder I could find contained printed gears, which I came to dislike, after using them for a while, as they do deterioate, so they must be replaced. Replacing them is not as easy as it sounds, as it really takes some skill and effort to get them perfect. I usually had to print at least 3 to get 1 perfect gear. And my printers are calibrated well.
In other words, I wanted to design an Extruder everyone could build. The printed parts are very forgiving if the printer used to print them aren’t perfect, and the other parts are easy to come by and of good quality, like the E3D hobbed bolt, instead of some generic bad quality hobbed bolt, without being overly expensive.
I wanted a geared extruder to make it more powerfull and accurate while at the same time having the option to use a small motor to save space and weight.
I did not want gears grinding at each other, as it makes noise and are more prone to backlash than aluminium GT2 Pulleys and belts.
Why not use E3D Titan Extruders? They are smaller, true. But they weight twice as much, unless you don’t use their recommended motor, and have gears instead of belts. While gears instead of belts might not mean a lot, for most people, the price of Titan is double that of the one I published. Times 5 and it means a lot.
I also created mine before Titan was published 🙂 Titan has a genius tract for the filament though, which is awesome!
I just have to have some lightning in my printers, so LEDs it is. Some years ago I bought a big roll of leds, which this is the last I’m now using. Really nice to just cut it into fitting pieces, solder them together and attach to your printer or similar.
I cleaned up the alu-extrusions using Acetone first before attaching the Leds.
Front LCD planning.
I sort of forgot it at first, but remembered I needed some wiring for the planned Panel Due 4.3 touch screen, which I want mounted up top right-side.
Using my trusty dremel to cut out a hole for the connector in the panel and also had to cut away small bit of the alu-extrusion to make room for it in there. I used some shielded 4-wire cable I had, which were perfect for this.
You might noticed it above – handles!
After adding the extruders the BeTrue3D printer got rather heavy but was ok to lift.. untill I put on sidepanels, which left me nowhere to to grab onto it.
I sawed a handle on each side, and aligned the holes up with the lower top-alu extrusion to give me a good grib. The panels holes are 1mm above the alu-extrusion and I’ve rounded the cut to make it comfortable to use.
I’m waiting for the new printbed from clever3d.de, and also the Y sliders. I am also waiting to recieve the 5 new heatsinks from reprap.me, which I hope to get any day, so I can plan a carriage for it.
That’s it for now, so have a good one untill next time.