if a robot builder on a budget to buy either this or that. which one ?
Well, I may not be fully
Well, I may not be fully qualified to answer this question as I have not finished my 3d printer yet. However, your answer is going to depend upon a number of factors.
1) Actual budget that you are constrained by.
2) A 3d printer can be cheaper for a number of reasons. First, the initial investment in the machine. Second, you need only buy the filament after you buy the machine. Third, software is free.
3) A CNC machine cost is driven by what materials are you wanting to be able to machine, Machining even soft metals requires a fairly rigid machine. Work envelope is another factor that will increase the cost of the machine. After the initial investment for the machine you then have to invest in all kinds of tooling which adds up very quickly. Addtionally, when starting out you can plan on tool breakage due to mistakes made. This means addtional cost for replacement tooling. And, if you build it yourself, you will need to invest in CAM and Control software. There are some cheap alternatives here. If you are only going to do light machine work (plastics, wood, circuit boards, etc.), you can get into a small CNC setup for a reasonable price. You will still need to buy some tooling, though far less than would be needed for metal working.
Don’t get me wrong, I love working with my CNC and other machine tools. The reality is that the cost of the machine is only a small part of what I have invested into that enterprise. I have probably spent as much for tooling as I have on the machines themselves.
Just some food for thought.
thanks for the points you
thanks for the points you made. Say having 300 $ which can bring a DIY 3D printer from Aliexpress. what would be the factors to look at before doing the somehow costly order.
Size, type of material and shape
These three factors can make a machine cheaper or more expensive. A 10cm3 machine usually costs 50% less th defectian a 20cm3 machine, and 90% less of a 40cm3.
Some 3d printers can be adapted as cnc cutter later. Cnc cutters are way faster, but 3d printers can make more things.
Then parts may arrive defective, mistakes in the assembly, bugs, and other things make support more useful than initial price. If price it’s a big issue, you can pre order works, or put it in a common place.
I started with a 3d printer with 20cm3, but i can change the head with a laser and make it into a cnc cutter.
Metalworking can get
Metalworking can get expensive very quickly.
There are deals to be found in used machine, but you have to know what you’re doing in order to judge a good machine and to fix it.
I think a 3d printer is a better choice for starting out.
A 3d printer can be very versatile. You can make some parts that are difficult or impossible to machine. And there are a lot of types of plastic. I bought a consumer machine from KickStarter, the Robox. It seems like it is a nice machine, but it gets into trouble occasionally. I just finished repairing it, today or tomorrow I have to test it, dial it in, and test it again. Then maybe I can start making robot parts.
Due to depression the fixing hasn’t been quick, though it should have been.
A few things to look at in a great 3d printer:
- Envelope size. You want one that’s will print the things you will need. Mine is around 10" by 6" by 4" (well, a tad smaller that that). There are things I’m going to want to print that are larger than that so I’ll have to print them in pieces.
- Heated bed. This makes things a lot easier. I was able to print several items in ABS with no warping.
- Enclosed print area: this may have been more important that the heated bed for preventing warping.
- A high temperature hot end. If possible, get one that will go up to 300c; this will allow you to print in things like Triton (a very hard, durable plastic as well as nylons). Low temperatures restrict you to PLA and ABS. I’m not fond of the way ABS smells, but with my machine it prints more reliably than PLA.
As to the things I want to print: robot parts, robot bodies, household stuff, and jewelry. I’ll probably also design some retro-futuristic gear to sell if I get that good.
Now I wish that I had gone with a delta printer. I’m looking at one of the larger deltas for a future project.
That’s just what I want to do.
When I get the money I’d like some basic metal working tools, but nothing too large.
I have non CNC shop…
And I can tell you like BrassFly, the tool bits alone can make you go broke! Also, CNC can be a bit costly hardware wise, not to mention, a bad design can have the machine destroy itself… I dont think a 3d printer can.
they also make quite a mess.
For me, I have manual machines (mill and lathe) and I usually work from designs on napkins and figure it out as I go, so 3d printing is a bit away yet for me. But for sure, the next step for me.
But your work is so nice. I
But your work is so nice. I loved the arm you built for the BRP.
The only thing CNC gets you over manual is that you get to take more breaks. 
Wawoo…great discussion. I
Wawoo…great discussion. I dream of a day where someone from LMR sitting somehwere in Africa, making custom limbs to the needy people. As simple as it sounds, it really changes the life of an individual who needs a limb.
Once I get a printer that
Once I get a printer that works, I will donate time/plastic for limbs. There is a foundation you can join that states the needs and hooks printers to the need. I’m supposed to get a new part that will keep my printer working (the frigging Bowden tube keeps coming loose during a big print).
I’m thinking of a Rostock Max or even larger for my next printer. I like the 11 inch diameter circle and as much height at I can make it. I could build furniture with that! The only thing is I’d need a better hot end if I want to do nylon.
I may not need a kit, because I already have 8020 extrusions; I can print the plastic parts; and the rest of it shouldn’t be too difficult.
It would be neat to have a large mill, because with a change of tooling, it could become a printer! But considering my shop will be in a camper van or trailer, I may have to keep it light.
3d printers can go kamikaze
I had a bug that simply ignored the input of the y endstop (software bug i suppose) and the printed has jammed the plate at full speed against the endstop, breaking it’s support.
Then the hot end thermoresistor was off by 5°, and in the first print i saw white smoke, an awful smell of burnt and then i saw that the filament was flowing from the sides of the hot end, not from the nozzle, overcooking pla to a brownish bubbly ooze. The instructions were saying to tightening the nozzle not to much in order to not to break the tube. It took a while to clean the mess, by heating the hot end at 150 and scrubbing it with a toothpick.
Then the z endstop was calibrated well. In the test home run it did well, stopping exactly at 0.1mm from the table. I didn’t see that the momentum of the axis bashed the endstop and lowered it a bit. I ordered a print and it did again all the home run, but z axis this time was lower than the previous, bringing the head in contact to the heated plate; scarring it for life before i could stop current.
Strangely enough, we need
Strangely enough, we need them here in the US, also. Especially for children. Traditional prostheses are very expensive and children outgrow things by before you have them paid off.
Unfortunately according to law I’m not allowed to print and sell or give away “medical devices” because that would require certifications that would cost more than our savings. However, I think we can claim they are four amusement use only, and that gets around the laws.
As long as I can do it, I will.
Kids sure will have fun with a proper arm!
There are lots of wearables that can be printed, like tutors for broken or misplaced bones, ortopedic slippers, jewellery, armor, thumb protectors for sewing, …
One nice thing for some
One nice thing for some printers: as long as you aren’t limited with your filament, they make some interesting filament types, including copper and bronze fill. These seem to have enough metal flakes that you can polish it to bring out the glints.
There is also a radiation resistant filament; I don’t know how well it does that, but it should be heavy enough to make a sturdy base for something that might otherwise need a piece of metal as a balance. Or a set of plastic knuckles.
There are lots of different plastics. Triton is available and is strong. Taulman3d has introduced or plans to introduce some medically certified nylon filament. Between the different filament colors and painting you can produce pretty much anything that doesn’t need the strength of metal in a 3d printer.
And I saw a while ago somebody in South Africa who is selling a three filament hot-end for deltas. Now, this isn’t three hot ends but one where the filaments desired go into the melting chamber and mix right before printing. And you can choose which filament(s) will be extruded. New things are being invented right and left.
I remember reading an
I remember reading an article about doctor using 3d prints made from MRIs or CT scans for fixing thing.
One was a birth defect or very odd injury and they printed the bones involved for this complex surgery so they could see it better in 3d plastic rather than just visualizing it from the images.
The other was a surgery to separate conjoined twins, which is usually extremely complex. Having 3d printed parts of the areas that the needed to operate on helped them decide on how the surgery should go and also allowed them to practice. I always, before, had envisioned doctors practicing in VR, but inexpensive 3d printers has changed the game for now.
Plus it is possible to do thing easily and to make changes inexpensively when creating artificial limbs. I’ve seen articles about dogs with artificial legs that have allowed them to run again. I saw an “arm spork” very young children (the child may not have had a hand, I’m not sure) so that the infant could eat just as messily as other babies.
There are even 3d printers for dentists so they can print out a crown without having to go through a lab. Now those printers are expensive.
So pleased
I am so pleased that people on this discussion finds it in their hearts to make & give a limb. It is so sad civilians in these places torn by crises we cannot reach to give limbs or a wheelchair…But everything must start with step even a very small one.