Precision 3D Printer Build - Worklog

Discussion in 'Hobby Engineering' started by aokman, May 28, 2019.

  1. aokman

    aokman Member

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    So I thought I would start a thread on this and share my 3D printer build from start to finish. I have been planning this for almost a year now and collecting parts and materials slowly. For anyone who doesn't know, I work on a large range of 3D printers in the field such as SLA, power deposition, DLP, SLS and FDM for 3Dsystems and Onyx.

    The main goal of this build is to produce a robust, industrial scale printer which high end parts, high precision and utilising as much recycled parts as possible.

    Primary design features for the printer:
    • Floor standing printer
    • Lower cabinet stand for long term filament storage that will be climate controlled
    • Climate controlled / insulated build chamber
    • Targeting 600x600x600 build envelope
    • External steppers from build chamber to minimise heat stress
    • Print bed will only move in the Z axis at the most to improve print reliability
    • Quad extruders
    • No extruder motors on print head carriage to minimise potential inertia and motor heating
    • High end lead screws and THK linear rails
    • 24v / 48v native power supply to minimise voltage drop and wiring gauge
    • High precision stepper motors
    • Switchable bed voltage to provide quicker warm up and maintain temperatures without cycling
    • 6060 extrusion
    • Little to no bed calibrations required, high repeatability

    For the stepper motors, I will be using either Sanyo Denki Stepsyn or Vexta 5 phase stepper motors. Currently the Vexta is top of my list, they have a 0.72deg step instead of the usual 1.8deg which drastically reduces cogging vibration and improves accuracy. All motors are made in Japan of course :) The steppers will be overkill of course but the goal is to be able to do micro stepping while still having torque in reserve.

    More info on 5 phase advantages:
    https://www.orientalmotor.com/stepper-motors/technology/2-phase-vs-5-phase-stepper-motors.html

    The heated bed will go one of two ways, either I will source a silicone bed heater big enough or I will be utilising heating element wires which I have already sourced. These are only rated for 7W @ 24v but I have tested them at up to 50v which achieves a very high power output and tolerant of up to 200c. I would prefer the heater element route as I would like to utilise a thick build platform to provide a large thermal mass to stabilise heating and minimise temperature variance across the bed.

    Power supply will most likely be a 24/48v Delta 1000W power supply to run everything. This may change if I use a silicone bed heater as they are usually mains powered and will suck up the vast majority of the power. The power supply is medical grade, can run fan less and runs 94% efficiency.

    But before we can start all this, we need tools to kick this project off. I have just received my beast Bosch Glide mitre saw that will do the bulk of the rough cutting. My old saw just couldn't maintain its accuracy and cost me time. First job is to wire my dedicated vac into the trigger assembly for auto starting of the vac with the saw.

    After this everything will move over to the mill where the extrusion will be surfaced to eliminate distortion and ensuring everything is squared up. I also have my new oscilloscope and bench power supplies on the way for development.

    [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]
     
    Last edited: May 28, 2019
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  2. SimParadox

    SimParadox Member

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    Look forward to seeing you build this.
     
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  3. aXis

    aXis Member

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    Last edited: May 30, 2019
  4. disco frank

    disco frank Member

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    why not get a shop vac which will do this without the need for trigger wiring ..
    I have a makita shop vac that i plug into the wall, then i plug my saw ( or what ever i want ) into the vac, turn on the tool, vac starts! :)
    also means i can move the shop vac around
     
  5. OP
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    aokman

    aokman Member

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    Thanks for the link, I will look into those and see how they compare to the Vexta’s :)

    I do have a shop vac but I find it a bit annoying moving it around from saw to saw and hoses hanging around etc. I have a few spare antistatic vacs with hepa filters that are a modest 450w and I wanted to dedicate them to a saw each. Ill post more this weekend as im making enclosures for them to seeing if they are powerful enough :)
     
  6. disco frank

    disco frank Member

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    ahhh ok got ya! yup would be annoying moving it to multiple pieces of work equipment!
    ope the build goes well! :)
     
  7. ShadowBurger

    ShadowBurger Member

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    Nice one :) will definitely be following along

    If you want to avoid the downsides of a Bowden tube setup, the Zesty Nimble extruder uses a drive cable to remotely mount the motor. Have got one on one of our printers and it works awesomely.
     
  8. OP
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    aokman

    aokman Member

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    Ok... so finding 5 phase stepper drivers turns out to be a challenge in it self. Plenty of Vexta drivers out there 2nd hand but finding the exact driver that came matched to these steppers is bordering on impossible at the moment.

    I have spoken to Oriental Motor and the matched driver is CVD528BR-K which delivers 2.8A per phase and micro stepping resolution down to 0.00288deg. I have found one suitable alternative from Autonics but only 1.4A per phase. They have a 2.8A model ready to go but cost prohibitive at $1000 per driver! Maybe the drivers could be run in parallel but yeah its a gamble and not ideal for this projects goals.

    They were kind enough to give me all the datasheets also which has been a massive help. Unfortunately no information of effective torque at 1.4A so will leave that road alone for now.

    The hunt continues for a driver, I am sure there is a newer replacement driver out there, just need to match the specs to find a supplier with 3 drivers in stock ready to go.

    This probably explains why I am one of if not the first to attempt this on a 3D Printer :lol: Challenge accepted though as the learning process will be very handy when things step up to CNC.

    [​IMG] [​IMG] [​IMG]
     
  9. ShadowBurger

    ShadowBurger Member

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    Is there going to be a measurable benefit to going with the 5 phase steppers over, say, a 2-phase, 1.8deg NEMA 23 or even 34, possibly with a gearbox on it? Certainly makes the driver issue easy to solve and I'm sure the combined cost of motors and drivers would be a lot lower

    Also - dynamat works great on stepper motors with the high-frequency noise. Just an FYI ;)
     
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  10. OP
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    aokman

    aokman Member

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    This link discusses the topic in depth

    https://www.orientalmotor.com/stepper-motors/technology/2-phase-vs-5-phase-stepper-motors.html

    How it has been explained to me by engineers working in drive systems:

    5 phase offers more usable torque across the RPM range for faster rapids
    5 phase offers the same or marginally more torque when microstepping instead of a deficiency
    5 phase offers faster acceleration and deceleration
    5 phase is unlikely to ever miss a step

    5 phase has far less cogging resulting in a smoother drive system. You can isolate the motors of course but there will still be harmonics and the shaft will still transmit some of this into the system.

    2 phase will obviously do the job but it seems that currently it is a cost consideration not a capability one so for now I will push on as I want to evaluate how good they actually are :)
     
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  11. OP
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    aokman

    aokman Member

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    Finally got the Revolution Rage 5s setup tonight also for the longer cuts. The Rage 5s and the Bosch Glide are a happy family :) Both running Bosch Multimaterial blades which cost a mint :Paranoid:

    [​IMG]
    [​IMG] [​IMG] [​IMG]
     
  12. Cpt Watermelon

    Cpt Watermelon Member

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    Followed. I love home brew 3d printer projects.

    Using Duet or something else as a controller?
     
  13. OP
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    aokman

    aokman Member

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    Shut up and take my money!

    [​IMG]

    Raided total tools and bunnings to collect some extra tools. Also found a local supplier of extrusion and high end heavy duty brackets. Picked up some 4040 and brackets for testing of the mounting and also 90 deg corners vs 45deg butted corners.

    [​IMG] [​IMG] [​IMG]
     
  14. OP
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    aokman

    aokman Member

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    [​IMG]

    A productive evening, tested out the first batch of 4040 to see what the quality is like and their bracket hardware. Brackets were shit, over by a few deg so if I went with them, I would have to machine everything square. Brackets were also drilled for M7 hardware and they supplied M8 T nuts. Enlarging 40 holes in aluminium with sharp Cobalt drill bits is NOT FUN.

    Anyway used up all 6M of extrusion testing by building a frame for the glide saw, dust extraction is utter rubbish so I have decided to evolve the design and enclose it. Wiring will start soon for the overhead LED lights, vacuum and 15A plug to run everything...

    Saw repeatability going from 90 to 45 to 90 etc is fantastic, on the money every time after dialling it in initially.

    I will have some discussions with the distributor and evaluate the 6060 quality.

    [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]
     
  15. OP
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    aokman

    aokman Member

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    [​IMG]

    Ok so tools are starting to roll in thanks to end of tax year also :lol: upgraded to the Metrix 3292 multimeter with full colour LCD. Also picked up my HP 6624A DC Lab Power Supply and what a beautiful beast she is! I am still waiting on the new digital scope with logic analyser to ship :(

    The HP Power Supply is insanely built for sure, a brilliant buy from a surplus auction and cleaned up nicely! Did some quick testing with my meters and even at 50v she is only out by 0.01% !

    Anyway we have enough to get started on the heated bed design and testing, I will be using the lab power supply to test them to destruction and hopefully find their happy place and what I can get out of them. The elements themselves are rated for 200c @ 300v AC.

    The design elements to be investigated with the heated bed design:

    1. Thermal safety
    2. Electrical safety
    3. Thermal / power output requirements

    Due to the amount of power being dissipated in the bed and the voltages that will be used, safety are the top considerations. Off the top of my head, the heated bed will incorporate dual thermistors for software feedback and control. This will be backed up by dual mechanical thermal fuses that will fail open if a software failure occurs.

    The heated bed will also be current limited to prevent crazy shorts from happening and also incorporate variable voltage so power output can be controlled dynamically without cycling on and off like cheap 3D printers do. This will provide greater accuracy of target temperature, higher reliability of components and also ensure stable system power supply voltages by not constantly switching heavy loads on and off.

    The heating elements I am testing at the moment are rated for 7W @ 24V but the power dissipation greatly increases as voltage rises, I have done brief testing with them exceeding 40W each but I need to control things more. I am setting the upper limit of voltage at 48v DC for testing purposes.

    I have investigated mains powered heated beds and at the moment it just poses too many headaches in Australia. Too much regulation around mains voltages, safety, liability bla bla bla.

    [​IMG] [​IMG] [​IMG]

    [​IMG] [​IMG] [​IMG]

    [​IMG] [​IMG] [​IMG]

    [​IMG] [​IMG]
     
  16. OP
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    aokman

    aokman Member

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    A lazy Sunday doing some testing with heating elements. Managed to get them to about 30W a piece @ 50V

    Even with a very large thermal mass 1 element is capable of hitting 100c in 60 sec. There will be 30 of them in total by the end. So far they seem to scale very linearly with current draw and voltage which is great for controlling them. Don't seem to be any surprises as temperatures go high either with resistance changes.

    I ran it as hard as it would go at 50v and it hit a brick wall around 195c. Curious to see what is causing this as it seems to be self regulating as it approaches 200c. More voltage is in order :lol:

    [​IMG] [​IMG][​IMG]
     
    Last edited: Jun 16, 2019
  17. ShadowBurger

    ShadowBurger Member

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    195c is plenty though, isn't it?

    These elements look fun, I'm sure I could find a whole bunch of uses for them :D
     
  18. OP
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    aokman

    aokman Member

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    Oh for sure that is enough heat for anything out there it was more to:

    A. Need to test them to breaking point to see if they fail open, fail short, catch fire etc
    B. Find out how much headroom I have / safety margin
    C. I was bored
    D. I wanted to see some sparks

    I have tested 3 of them today in parallel which put out close to 90W. Temperature climb at peak efficiency is almost 4c per second :leet:

    I will connect the power supply rails in series and then I can push it to 100v DC which should guarantee a failure of some sort... :lol:

    [​IMG]
     
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  19. OP
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    aokman

    aokman Member

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    So the options are starting to close in, I have the extrusion for the heated bed for some initial testing, it is heavy at 4.5kg per section putting the bed frame at 18kg :lol:

    I will be testing heating the entire frame but It is starting to look like the thermal mass and surface area is simply too great to be reasonably heated. I am still testing but my 2nd game plan is to use a ceramic base over the frame for insulation and stability, heated bed followed by a copper and aluminium plate sandwich for the hot side. The copper and aluminium plate would be thermal epoxied and pressed together followed by machining.

    Silver solder was used for testing to ensure the melting point is well beyond the temperatures in use.

    [​IMG] [​IMG] [​IMG] [​IMG]
     
  20. mrbean_phillip

    mrbean_phillip Member

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    Looking good, will keep an eye on this :)

    Need to start my build soon too, have all the steppers (0.9deg), electronics (DuetWiFi), heaps of spare 8020 from my sim-rig build....but need to order the screws and rails....blah....

    Anyway, keep up the good work, will keep an eye on this.

    Cheers,
    Beano
     
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