"I'm going to build 3d printer" - typical beginning i think. But it's true - at last i'm going to do this. But i'm completely new in this - so i have more questions than answers. And if you don't mind - i, going to do it here. My be we'll have something good as result (at least i hope so). Now i'm at design stage. What i want as result. And some questions:
Question one - is it better to use ball screw (like in CNC)? Belts are faster but ball screw gives more accurate positioning (as i know). Plus with screw i can use more heavy printing heads.
Both belt and ball screws have back lash, the stepper motor moves a very short distance before the screw or belt moves. The only approch that doesn't have a back lash is a belt or cable in tension and with the ends fixed. One end provides the tension with a spring. Thus the only issue is stretch. Drums with a single layer are used to take up the cable. Thus length changes with distance, trig, so the angle must be very small.
Professional printers for ABS and other materials have temperature control that keep the plastic above the glass transition temperature, one cause for shrinkage. Thus support material is used and the parts are metal.
I'm new to 3d printing myself. I got a sunlu s8 as a gift it has a build surface of 310x310x400 with two belts which I did have to tighten. I plan to make screw tensioners for it. It also has two screw drives for the z axis that work together. I am going to but some tmc chip in line from driver chip to the stepper motors to reduce feedback and they will smooth out the movement. They will also quite down I'm going to be put a video on my YouTube channel soon of me putting them in. The channel is mebgizmo 3d or you can find it looking through videos on sunlu on YouTube
Like Core XY with belt tention?
Rather than invent the wheel myself, I got a Tronxy X5S kit off gear best.
it comes in a box and you have to put it together and add any upgrades, but I learned a lot, build area 330x330x400mm or so and it prints everything up to 345c or so very well. I put an enclosure around it and it prints abs very well. It's a good introduction and kit was a good price at 274.00 right now they are running 299.00 but they have also upgraded the power supply to 24v. mine is just 12v but with insulation on the bed I can get it to 100c. I would suggest putting one of these together will give you lots of insight into how to design and put together your own printer. :)
Like Mark said, the cheapest way to start is to buy a damn kit and make it work.
My FLSun is that big and I can tell that for such a volume there are issues with printing towards the top of the volume, shakes, vibrations, misalignment, etc, if the printer is put together with 20x20 Al profiles like mine, best if 40X40.
Than in a year or two when you got more familiar you can make your own model, like I do now.
Go read the other discussions here and you will find bunch of information posted by members in the comments.
Also it is advisable that the Z axis move up and down thus not having your build plate doing the Y axis movements, makes the machine shaky.
Also is better if you make a machine ready for tool change, makes life a doddle.
Buy a cheap one and figure out how to use it, then use that printer to make the printer of your dreams!
I did the same thing as you! but I did it back in 2007 when RepRap was new and there wasn't anything out there except for DIY Mendel, Prusa wedge. My 12"x12"x14" Prusa clone is not running yet but I could totally get it running if i spent time in Marlin.
I ended up buy a makerbot mini in 2015 because I wanted to finally print something!!! The wonderful part about makerbot is the software and that's about it. I traded stuff for the Original Prusa i3 MK3 kit. I should have saved my money and done that in the beginning!!!! or go to AliExpress and buy a 98% clone of the Prusa i3 MK3s. It just works and it works well, I love that machine!
There is a massive building learning curve, firmware curve, CAD Curve CAM/Slicer Curve and how do I make this thing keep working curve. Its best to remove some of those curves before making your own.
I guess we should have asked, do you already have a printer?
No - I don't have one. But i think i should say, that i'm not complete nub i'm new in 3D printing area. I know what is CNC and how it works and have access to it, i worked with arduino boards and simple FPGAs (so i'm not afraid of electronics). I designed and build some geodesic dome houses (it's not the same as 3d printers - but...) i want to say, generally that i have some basic knowledge and skills. But it is much more simple to ask - "is 20x20 extrusions enough or i should use something else" than to spend some days for modelling and calculations. I can buy printer kit and i'm sure i can make it work. I can (with the help of commuity) create custom variant (almost sure). But this is longer way (before first print). May be i should ask "I can buy (i'm sure) and I can build (i'm almost sure 95%). - What way, you think, i should choose?"
Tension does not insure removal of backlash in timing belts because there is always a gap between the teeth in the pulley and the belt teeth. Alternately if contact is make between the teeth of the two that contact has an angle. Which means that any dimensional difference between the two between the points of contact will change the radius that the belt is on, thus distance traveled to angle.
Cables have the advantage of being able to change directions so work well in core XY applications. So long as the tension represents the majority of the load of compression places on structure then the stretch and compression will be constant and the loads from the moving components insignificant.
The reason screws are used is that the loads placed on them do not result in much deflection, they are well within the linear range and at the low end most cases. Timing belts are typically well into their elastic range.
So cables will be similar to timing belts in that to get flexibility around pulleys the fixed tension that can be set can be high to minimize the cable size or belt size but the load added or removed by the printer components should be small in comparison.
I am interested in DIY CNC with concrete base and some major components. In may professional life as a mechanical design engineer have not worked on machine tools that demand precision motion. But have pushed the limits of materials working in aerospace. Did a lot of analysis on a hot water drilling rig for the South Pole to install a netrino Telescope, ~ 80 holes 1.25 mile deep into the ice where dozens of sensor were put into the 2 ft. hole before the ice reformed. Been operational for ~ decade.
I feel its like this either way you decide take you time, if you buy one I would take pictures then reverse engineer it so you see everything for you and feel it out but when putting it back together remember the square to get your 90's lol. And the same with building from nothing research everything and going with what you feel comfortable with.. II know either way I wanted to see you get it done the way you want because that is the other part to making I think is how you feel about what you have done. I'll support you either way and give advice. And I would go with the 20x20 with angled supports and base clip tied in on the 90 for base and tower
Oh CNC's are my topic man!!
I custom built a 4'x4' plasma table... (story for another time). its not working yet either. I am a mechanical CAD Designer and building a CNC looked simple enough to throw together. Its not.
However, it helps to have friends that can come over to look at your machine and say. yes or no.
You are in a completely different situation than I was! Every store on the planet sells 3d printers. Find a china machine you like. I personally like the ripoff cones. Like a Ultimaker 2 or a Prusa mk3s because those machines are constantly improving vs the china machine that are changing all the time because its easier to replace parts and sell again with zero company support.
I am not sure which style of machine your looking to build?
2020 is enough. Most of the china machines are 2020. its super easy to find and its very cheap. My Zaribo is 3030 only because i wanted to copy it's workbook. I also built the Modix Big60 which is 4040. Its over kill but solid.
Having both bought and modified, as well a scratch-build a printer, I will give you my thoughts.
2020 rail should be reserved for CoreXY machines with 200x200x200mm build volume or less, maybe 250mm cubed if its well reinforced in the corners and joints. Once you get up around 300x300x300mm, frame parts will start exceeding 400mm in length and flex becomes an issue.
I wouldn't personally build a 300x300x300mm printer from anything less than 3030. I've gone light on material in the past and rarely have I not regretted it. If you use 2020 and realize its not as stiff as you'd like once built, you're either stuck with it or basically rebuilding the entire printer. Do it right the first time. It's a lot harder to regret spending an extra $50 on extrusions than it is to wish you just spent the money to do it right the first time.
As for the belts vs ball screws, belts win, no contest. If you go ball screws, especially on x and y, it's going to be one slow printer. Remember, any mass you add needs to be moved by the steppers. Accelerating a ball screw takes a lot more effort than a belt. And having a ball screw attached to the X and Y axis adds a lot of weight. Once in motion, that weight is inertia your steppers need to overcome when slowing, accelerating and changing direction. That is bad for both speed and precision.
There was a printer that came out a year or two ago (from China) that used leadscrews on X and Y. It would print at all of 40mm/second or something like that, which is exceedingly slow for a top speed.
One thing to keep in mind with FDM 3D printers is they are not precision machines. Not by a long shot. Precision is hundredths of a mm, or even down to microns, where most FDM printers do well to hold a couple tenths of a mm tolerance. I seriously doubt youre going to notice any difference in print quality by using ball screws. However, it will slow your printer noticeably and leave a good bit less cash in your pocket.
The printer I built is a cartesian with 300x300mm bed and 250mm of z travel. It uses two steppers on Y and Z with dual lead screws, though I'm switching to belts and 5:1 gear drive steppers on the z axis as they're just easier to maintain and eliminate Z banding (though I dont have any noticeable issue). It has dual linear rails on Y and z and a single rail on X, all 12mm rails. The main structure is 4040, 2080 and a central 4080 C-beam, all from Openbuilds. Its extremely rigid and has maintained square since I first built it. I obviously could have used much smaller extrusions than I did, but at that point why would I bother building a printer when I could buy one already built like that and save a lot of hassle?
I designed all the stepper and pulley mounts, belt tensioning systems, corner brackets and mounting plates, the print head (sort of a BMG clone with V6 hotend that has an integral mounting plate that bolts to the linear rail carriage and has mounting points for cooling ducts and fans).Basically, I tried to avoid using anyone else's designs and make as many pieces as I could. Things like the hotend and pulleys I purchased, as it doesnt make much sense to spend a day machining a heatsink when I can buy a complete hotend for $60.
My printer doesn't print near as fast as my coreXY printer does, but its extremely consistent. It just works every time and needs very little maintenance. The only time I've had prints fail on it have been because I screwed up the slicer settings.
Final thoughts, if you dont have a printer already, buy an Ender 3 and learn how to diagnose issues and tune your slicer profiles. Theyre a very solid and affordable printer that will teach you a lot. If you build a printer with no printing experience, I feel it may be difficult to diagnose any potential issues and your learning curve will be much steeper.
If you already own a printer and have the basics figured out, build your own. You're already far ahead of where I was when I decided to build a printer. I had never used CAD before I decided to build my printer, and had to learn as I went. This probably shows in my printer to anyone skilled in CAD design, as my parts are admittedly a bit "blocky", but they're correct in dimension and function so it's fine with me. I'll get better in time, and this isnt the last printer I plan to build by any means.
Whatever you decide to do, good luck with it!
Now that was a nice story Kenny, could you just copy that into your own discussion here in the group and add some images or links to YouTube for how is it looking, how is it printing, and eventual changes you made or will make to improve it?
Starting a new discussion is easy, just click once on the red rectangle in the left corner that has a +NEW writing on it.
Stories like this make my day, just makes me feel I am not the only one in this universe that made it from scratch and is willing to do some more.
I plan to do exactly that as soon as I have the time. I’ve been super busy with work lately and haven’t been home enough to make it happen just yet, nor have I been awake and coherent enough when I am home to write things out so others can actually understand what I’m saying. I honestly fell asleep twice typing my last comment.
I should be slowing down a bit in the next few weeks and plan to upload the printer and my reasons for designing it the way I did ASAP. It’s not perfect, as I would probably do a few things a little differently if I were to start over. But it came together much smoother than expected. I thought I would have a lot more fitment issues and pieces I needed to adjust to get it up and running. But it went together near perfectly with only some minor filing and redrilling a handful of holes that I had made a millimeter too small (someone should have checked the print 🤦♂️).
Thank you for the kind words of encouragement. I’m sure you’ll see it up here soon.
don't worry about spare time, the Corona Virus lock-down will give you plenty of time.
go for it, it is a pain in the but, moving cameras around to catch the action, but in the end a 20 minutes video (that might cost you over 50 hours of work) might help somebody somehow.