3d-printed Halbach Motor - Building Instructions

hi how are you in this video I will explain how to build a 3d printed brushless Halbach array motor most of the work is quite simple and parts only need to be 3d printed and then assembled in the correct sequence winding the compromise isn't much more complicated however it will require some more time and careful working to get started you need to purchase all the required hardware large neodymium magnets smaller neodymium magnets animals copper wire small ball bearings a large ball bearing a shaft shaft colors threaded rods and a bunch of nuts depending on your application you should prepare m3 bolts and nuts washers connecting cables heat rink and plugs as tools you need a decent drill press a solder iron and various screwdrivers make sure your 8 millimeter drill bit is in a good shape after downloading the STL files 3d printing can be started basically the motor consists of three main components whereas each component is divided into two halves there is the rotor the stator core and the stator mount all parts can be printed with 0.15 millimetre layer height except of one part there is no support material needed the rotor if the slots for the magnets is the largest part the second part of the rotor is like the lid of a jar and holds the magnets in place the third smaller part of the rotor named color is needed to firmly lock the shaft to the rotor use ptg for all these parts that's the material I have tested abs maybe works as well but you probably need to experiment with shrinkage the rotor needs to sustain high centrifugal forces hence our recommend for shale layers and 50 to 70 percent in will since it takes several hours to print the rotor I recommend to first print this small section fit the magnets and tune the print settings if needed the shaft color is the only piece which needs to be printed with supports enabled this data core is the winding form of the copper wires it consists of two symmetrical parts I recommend to use magnetic PLA from proto pasta pla has a problem at higher temperatures but the metal powder not only helps to increase the magnetic flux but also helps to dissipate heat to gel layers and 95% in Vellore recommended the stator mount is also divided into two halves it firmly locks the stator core and allows to mount the motor on a chassis it is printed with ptg like the rotor print it with three shell layers and 70 to 90% infill after all parts are printed they temporarily should be assembled and may be cleaned up use a drill press to adjust the hole for the shaft in the cool lubricate the drill bit and drill at low rotation speeds cut and not melt the fat [Music] press in all the ball bearings if it's too loose you can add some captain tape but don't use painters tape fix the nuts on one end of the rods with threadlocker glue push the two halves of the stator course under the stator mount and align the teeth headers fix them with painters tape for later winding work now the wires need to be prepared animal copper wire with 0.45 millimeter diameter is needed six strands are combined into a single cable it needs to be 5 metre long twist it 20 to 30 times and wind it up onto a small spool the copper wire of one spool will weigh roughly 50 gram three spools are needed for winding the three phases I recommend to wire the motor with the Y configuration hence the three terminals of the cables can already be soldered together and isolated with each drink if you want to experiment with Delta or Y configuration keep all the terminals unconnected the stator if all the wires looks like this the three phases are colored in yellow red and blue the cables are placed with alternating phase and direction into the slots a single phase consists of nine smaller coils arranged around the stator now let's start winding grab the first cable phase a and place it into a slot which has a toothed head fix the loose beginning of the cable with some painters tape bend the cable into the directions attested by the toothed head skip two slots and place it beneath the neighbor toothed head into the third slot use a piece of wood or plastic and tightly push the copper wires into the slots never use a metal tool like a screwdriver because it damages the isolation better use my 3d printed via pusher why are the cable back to the slot where you've started the first turn of the first coil is now completed repeat this procedure and make three more turns if the last turn place the remaining cable inside the stator it will stay there until the next round now get the second cable it's phase B repeat exactly the same as we face a but start with two slots offset the overlapping wires will help to fix the wires beneath when done also put the spare cable inside the stator redo the same pattern with face Z great 1/9 of the winding work is now finished the rest of the work isn't much different get a spool of phase a out of the interior of the stator and continue then do phase B then Z and so on when you get to the very last coil of phase Z you will realize that there is something fishy the cables need to be vibin eath the first coil of phase a winder space with a wooden toothpick unroll the remaining cable from the spool and start weaving the result of the weaving work not only looks great but it also secures all the cables now it's time to insert the stator mount feed the three begins and the three ends of the cables through the holes you probably need to bend the windings outwards in order to avoid jamming them between stator mount and stator core make sure the two smaller ball bearings are well inserted also insert the four threaded rods with the nuts flute on one side be careful to not damage the isolation of the copper wires if you sold it already the cables for the Y configuration there are only three wires to feed through the holes for finishing the wiring you need to solder some connectors and protect them with heat shrink well done this was certainly the hardest part of the motor as next we are going to insert the magnets into the rotor the problem is the variation of the quality of these magnets they are differently strong and heavy and this could cause a badly balanced rotor therefore we are going to measure the weight and the force of all magnets our main tool is a little scale the absolute accuracy is not as important but repeatability needs to be good stick all the large magnets on an iron bar orient them with the same polarity north or south upwards label the magnets with a number for later identification when measuring magnets with a scale we have to be careful to not disturb the result by magnetic components of the scale itself avoid any magnetic objects on your desk even a screw hidden inside the table could corrupt the numbers this is a simple construction for measuring the force take a wooden bar and put one end onto the scale and the other end on a block of wood place the magnet on the bar mark the exact position and tear the scale push a ferromagnetic object beneath the magnet also remember or mark that position I found a piece of ferrite with a similar size like the magnets another chunk of metal for example some nuts will certainly work as well tear the scale for each magnet before measuring the force make a note of all the values and select the 18 strongest magnets for measuring the weight I'm using a similar construction with a wooden lever this time the scale needs to beat aired only once without the magnet also write up all these values the plot illustrates the distribution of my magnets the variation of the magnetic force is very significant but it has no influence on the centrifugal forces however the variation of the weight matters imagine if all the heavy magnets were located on the same side of the rotor for this reason we are going to insert the magnets with a special pattern the picture shows the 18 positions of the slots for the main magnets but these numbers are not the identification numbers of the magnets from your notes they indicate the weight one is the location for the lightest magnet and 18 is the location for the heaviest magnet when inserting the selected and sorted magnets into their designated slots their polarity needs to be alternating the label on the magnet helps to identify the correct orientation if a magnet was inserted wrongly you can easily remove it by pushing a pin through the hole from the other side of the rotor also measure force and weight of the smaller magnets the plot for my magnets is revealing a huge variation in force the strongest magnet is almost three times stronger than the weakest magnet and I bought them all from the same seller for inserting the small magnets the large magnets will help if the polarity is wrong the small magnet will float in its slot turn it around and with the correct polarity the magnet will snap into its proper position certainly this sorting method isn't the optimum for a perfectly balanced rotor but it's simple and helps to avoid the worst case ok the motor is almost finished we need to do the final assembly the color needs to be fixed on the shaft in fact there is a smaller metal color sitting inside the plastic color the set screw needs to be quite long and extend into the plastic color the color has four additional holes which can be used to directly mount a pulley or a propeller there is also a color available with two internal metal colors this version can transfer more torque from the rotor to the shaft insert the shaft into the rotor and fit the color into the rotor spokes slide the completed stator into the rotor maybe you first try to close the motor without that large washer if the stator doesn't slide force or back you're done in my case the washer was needed probably the clearance depends on the printbed calibration turn the rotor by hand and carefully listen if there is some noise from cables which are touching the rotor remove this data again and find the reason cables are maybe not properly in their slots or maybe the cables are touching the ring of the rotor basically the rotor is already well fixed but if there is a heavy load directly attached to the shaft I recommend to fix another metal color on the side of the stator mount I also strongly recommend to build a simple wooden test stand for the motor the four threaded rods are used to fix the stator don't tighten these nuts too much because there is only plastic on the other side if the nuts come loose while the motor is running you should use locking nuts instead connect the three wires from the motor to a regular ESC I'm using my homemade or Dino based server tester for generating the control signal it is also a good idea to alternatively use an RC transmitter and the receiver then you can do the tests from a safe distance for the very first test you should really use a battery with a voltage much lower than the nominal voltage of the motor the motor will spin not as fast and in case something goes wrong the damage is less severe with 8 volts from the battery the motor should be slower than 2,000 rpm [Music] [Applause] [Music] without a load the motor draws much less than 1m I'm attaching a propeller and led it around in reverse direction because I want to test the phone and not the thrust for this test I'm using again the small battery [Applause] [Music] with the big battery I decided to go outdoor [Music] I hope you enjoyed building this motor together with me and I'm really curious to see your applications feel free to post comments and also check the links in the video description

Channel: Christoph Laimer

Views: 1,738,954

Rating: 4.9468346 out of 5

Keywords: building, instructions, diy, home-made, halbach, brushless, dc, electric, motor, outrunner, ultimaker, makerbot, magnetic-pla, pla, petg

Id: YsSm65DAcCg

Length: 15min 39sec (939 seconds)

Published: Wed May 03 2017

Reddit Comments

[u/CaptainDave]

Badass.

[u/almostreddit]

Impressive

[u/mateataneight]

I hope this guy is thinking about his safety so he can keep making cool things. Some of those experiments at the end look pretty sketchy.

[u/streetmitch]

my final high school project was something similar to this. just thinking about winding that wire was giving me bad flash backs.

[u/maddrok]

This was very interesting, hardly comprehend what is going on but it looks good and doable