Since I have learnt so much from others on the the web I though I would share my printer build and other related 3D stuff in the hope it might help someone else.
Thanks for looking
I was thinking of designing my own extruder but rather than reinventing the wheel I opted for one designed by the guys at Infill 3D. I used this one on thingiverse. It has a 5:1 gear ratio using herringbone style gears and suits the nema 17 motors I am using for this build.
I printed it out on my UP printing using fine quality and a layer resolution of 0.2mm. It printed very nicely and I vapor smoothed it to add to the bling factor since it will be mounted on the outside of the build chamber. I also thought that the red colour look squite nice also
The extruder will be mounted on some 30x30mm aluminium extrusion but the mount that Infill 3D designed did not allow for this so I knocked one up in Inventor and printed it out. This was also given the vapor smoothing treatment to match the extruder. It is secured with M6 T-bolts and can be found on thingiverse here
I still need to pick up the bearing to suit the extruder and make the M8 hobbed bolt, then I can calibrate the extruder and give it a whirl.
3D printed extruder bracket front view
3d printed extruder bracket rear view
Infill 3D bowden extruder mounted to the bracket.
5:1 gear ratio Herringbone gear train
Since the extruder is going on the outside I needed a spool holder spindle so I designed one of those also to allow mounting to the 30x30mm extrusion with T bolts. It was designed to suit the Verbatim filament spools I currently use and also 3rd party spools that are a completely different size. Since the Verbatim spools are narrower I needed to print some spacers to keep it from sliding back and forth on the spindle. To stop the spool falling I added a left hand thread and nut to the end of the spindle. Since the spool unwinds in an anti-clockwise direction the LH thread means the nut cannot come undone accidentally. The thread is a 3mm deep 60° angle with a 4.5mm pitch. This spool holder can be found here on Thingiverse
With some time off work it would be a good time to fabricate the frame parts and put it all together.
The BOM so far is as follows:
- 3 lengths of 30x30 aluminium extrusion for the uprights.
- 6 x 12mm linears rod for the carriages to run on
- 12 x 3D printed 12mm rod end supports
- 6 x LM12LUU linear carriage bearings
- 12 x 21mm external circlips to lock the bearings
- 12 x 10mm diameter N42 magnets
- 6 x 10mm diameter x 8mm bore carbon fibre rods
- 16 x 30mm right angle brackets
- 4 x 47mm Nema 17 steppers, 1.8° step, 47 N.cm
- 3 x right angle brackets for mounting the steppers
- 6 x T2.5 16T sprockets.
- 6 meters T2.5 polyurethane timing belt with metal reinforcement
- 9 x 625zz bearings for the stepper shaft supports and belt idlers
- 3 x laser cut 6mm plates for the bas, bed and roof
- 1 x custom all metal hot end
- 1 x 3D printed end effector
- 3 x 3D printed linear carriages
- 3 x 3D printed stepper shaft supports
- 3 x 3D printed adjustable belt tensioners
- 1 x 40w heater cartridge
- 1 x ptfe bowden tubs, 2mm ID
- 1 x 5XC Smoothieboard
- 1 x LCD panel for the smoothieboard
- 1 x 5v voltage regulator for the smoothieboard
- 1 x 24vdc power supply
- M4, M5, M6 and M8 bolts, caps screws and nuts
- blue loctite to keep things from coming loose
Still to purchase are the end stops, themistors, extruder drive wheel and extruder nozzle and I still need to print the extruder parts. I like the 5:1 extruders so will go this way I think. the extruder that RichRap uses has been proven to work well so a good place to start.
I am still undecided on what type of heater bed I am going to use. A 240vac version will be much easier and draw less power and I am steering towards a silicone heat pad at present but we will see.
Frame Uprights:
The three 30x30 frame uprights are just under 1,100mm in length and were cut using a mitre saw.
Then, since each end of the extrusion will be bolted to the floor and roof plates I drilled a 7mm hole then tappped an M8 thread into the extrusion. The important thing here is to ensure there are no burrs as this will cause the extrusion to not sit flat when bolted to the plate and therefore introduce the wobble in the frame.
Floor, Bed and Roof plates:
I opted for 6mm thick aluminium plate for these parts. The original plan was to drill all the holes using the mill and DRO but sinve my mill only had 250mm in the Y axis it would be inpossible so purchased the plate and sent it, together with the .step files over to my local laser cutter to cut. the results were outstanding and given that Delta printers rely on acuracy, this was the most important thing for me. Cost wise the 3 plates cost $110 to cut but well worth the money.
Assemebly and drive parts:
Having the base, bed and roof plates laser cut was one of best things I could have done as the accuracacy is second to none. Once the smooth rods and vertical extrusions were cut to the correct size it was jsut a cose of bolting the peices.
I started by bolting the vertical extrusions to the base plate first, fitting the stepper motor shaft end supports into the extrusion then fitting the 3 stepper motors. This was much easier to do without the bed plate fitted. The stepper motor shaft supports have a 625zz pressed into them and a 5mm nut and cap screw which goes through the bed plate. This allows for adjustment of the bearing centre height to suit teh stepper shaft. The idea behind the supports is to stop deflection of the stepper motor shaft when tensioning the belts which will stop premature failure of the shafts.
supports with 625zz bearings
fittind to the alloy extrusion
motor removed after locating the bracket so the cap screws can be tightened
all mounted
stepper shaft captured by the support
Next to be installed was the bad and roof plates, linear shafts and carriages. The bed plate is supported by six 90° angle brackets which allow for adjustment of the plate. The roof plate is bolted to the vertical extrusion and has three angle brackets. The 12mm linear rod passes thought 12mm clearance holes in the plates and are secured with 3D printed mounts that are bolted to the plates. All in all it make for a very strong and rigid structure.
90° angle brackets
12mm linear rail mounts
bed plate fitted
fitted linear carriage
12mm linear rod before mounts were fitted
Belts and Tensioners
he belts used as mentioned earlier are T2.5 polyurethane steel reinforced running on 16T sprockets. I opted to use sprockets also for the idlers to ensure the belts are not stressed when going around the diameter. The tensioners were 3D printed with 2 x M5 bolts and nuts fitted for tensioning and an angles slot to allow quick removal of the idle pulley. Like the stepper shaft supports they are also made to slot into the alluminiun extrusion profile for added rigidity. The pulley is supported each end with a 625zz bearing so runs very smoothly with little friction. As seen in the picture below there are also 2 M4 cap screws going throught the body of the tensioner to stop the printed part ever delaminating under load.
close up showing the idler pocket
fitted to the roof plate
2 longer bolts are the belt tensioners.
The belts were then fitted to the carriages and cut to length. Since this is a custom build this involved removing the alluminum upright to gain access to the rear of the carriage. Once done the upright was re-installed and the belt tensioned. This was repeated for the remaining two towers
Diagonal rods and rod ends
The diagonal rods are made from 10mm OD x 8mm ID carbon fibre tube that was cut to length using a jig to enable all the rods to be the same length.
The rod ends were made from M8 mild steel bolts. In the lathe I turned the flats off the bolt head, then using a 10mm ball nose end mill cut the pocket into the bolt. By using rocol cutting fluid it is possibel to get a near mirror finish on the parts. To ensure all the pockets were the same depth the bolts were pucher hard against the lathe chuch, and a stop was fitted to the tool pust for teh drill chuck to hit when home.
The treaded portion of the bolt was then cut off leaving a 27mm shaft plus the head. This provides plenty of metal for the magnets on the effector and carriages to hold onto. The metal rod ends were then cecured into the carbon fibre rods with epoxy glue. To ensure they are all the same length a jig was used consisting of 10mm balls and my mills x axis table and DRO.
pocket after drilling
end stop for the drill chuck
finished rod end and one inserted in the carbon rod
(not the rod is not cracked, it is just the light reflection)
These were then fitted to the linear carriages and end effecto and finally it is starting to look like a 3D printer.
Endstops
For the endstop am using small mechanical switches bolted so custom mounts with M2.5 bolts. The mounts are fully adjustable via a bolt that goes throught the roof plate and again slide in the alluminium extrusion. There is also a bolt to lock the mount to the extrusion when happy with the position.. The limit switch arm is activated by the top of the carriage. The wring for the swithc is run inside the extrusion keeping things neat
M2.5 cap screws securing the switch
back side showing the switch and extrusion locking bold
mounted to the upright
switch location when fitted
All assembled
All assembled ready for the electroinics
The printer stands 1100m high and is 540mm wide. Weight wise it feels around 25kg.
Next to my Up Mini printer
Smoothieboard
After much research I bought a smoothieboard 5XC controller from Robotseed and couldn't be happier. Admittedly this was the part of the build I was most worried about especailly after reading some have spent weeks trying to get their printers to work. Well, my worries were unfounded and the Smoothieboard has surpassed all my expectiaions in build quality and easy of uses.
The guys at Smoothie have done a great job with the instructions and almost every question I had could be found online. Also the SD card that is pre-installed in the board has all the files, software like Slic3r, Cura and Pronterface, plus masses of documentaion to cover everything one could imagine. The user forum located here was also great for getting questions answered fast by the developers.
The kit I bought had all the conections pre-soldered but the user still needs to install the crimp connectors and fit them to the plugs for your steppers, end stops and other parts. To be doubly sure there was a good connection I also soldered the wires to them
The installation guide located here covered pretty much everything I needed to know and within a few hours I had the printer up and running. There is no firmware to muck around with and if anything needs to be changed it is done by opening the config file in a text editor, changing the value, saving the file and rebooting the board.
For a delta printer a few extra lines are codes need to be pasted into the text file. This allows the input of the ARM_LENGTH and ARM_RADIUS. I also altered the max stepper current which I set at 1.3A, although my stepper have a maximum current of 2.5A. This has not affected their performance and my initial movement tests at 150mm/s proved that. Other settings that need to be changed are steps_mm, speeds for homing, and possibly the motor direction.
You also have the option of downloading other peoples config files for delta printers and use their config but this would be more useful on generic printers, not custom ones. Most of these can be found on GitHud.
Anyway, I wired the motors and enstops and loaded the supplied Windows drivers for the Smoothieboard. The baord was then connected the board to an external 24vdc psu and the board plugged into my computer USB port. The best thing to do here is to eject the printer via the "Safely Remove hardware" icon to avoid any hangups. I found if left mounted Proterface would freeze occasionally. Then go into device manager and set the USB port speed to 115200 to match the smoothieboard.
I opened Pronterface and connected to the smoothieboard via com6. A few settings in Proterface needed to changed like build area etc and this will be different for every printer. Pressing the console home icon casued the carriages to head upwards until they hit the end stop switches, then they backed away and moved up slowly for a second more accurate position. I was not happy with the fast homing speed so I redued the fast_homing value in the config file, saved and rebooted the board. A second test was much more to my satisfaction.
Bed height was set by homing the printer with a G28 command, and loweing the carriage down manually using the pronterface console until it was a sheet of paper thickness off the bed. Then send the command M306 Z0 followed by M500 to save it. This is not a complete calibration but enough to move the head up and down without crashing and more than sufficient to allow air printing for motion testing etc. A more complete configuration guide can be found here
The video below is a motion test at 150mm/s . I printed a pen mount that fits the end effector so I could see what is was doing when printing. The result was fantastic.
I also have the full function LCD for the smoothieboard that needs to be wired in but I first need to work out which pins need to soldered to the board for it to run. I have the V1 shield but there is a V2 shield ariving soon.
I will try and print an extruder thisafternoon if all goes well but will need to wait until some thermistors arrive to test the extruder properly.
I have started printing the linear carriages and the first batch have turned out well. They are designed to have 2 x LM12LUU linear bearings fitted, which are clamped by the means of 4 x M4x16mm cap screws and 2 circlips on each bearing to stop it moving up and down. They were printed on my Up Mini at a resolution of 0.2mm, fine quality and 1/4 fill to keep the weight down. I will say though, make sure the part is printed with teh pockets for the balls facing upwards and if facing down, even with smart support the pockets are not radiused correctly.
I am using GT2.5 open ended belts so the carriages are designed to grip both ends. I printed and tried a few integrated belt gripper designs before I settled on the one below. It is made so the belts pass over each other and are secured so the ends pull from the opposite side of the carriage, pulling the print layers together, not apart like it would if each belt was attached from the top and bottom. This is important especially if the chamber is heated as I don't want any delamination of the part. This also means I don't need to worry about too much belt tension breaking anything. A 6mm long piece of 1.75mm filament is pressed into the eye where the belts fold over and becasue the teeth mesh together they cannot pull out. I yanked on both belts really hard and there was no movement so I am very happy.
carriage with belt fitted and securing nuts and bolts
close up showing the belt fed into the carriage and the small pieces of filament
locking the end loops
The belt grippers are located dead centre between the linear rods in both the x and y direction so there will be lateral forces on the bearings from the belt pulling the carriage up and down. This also means that the steppers are mounted off centre to keep the timing belt centered to the carriage.
Like the end effector each carriage has a 10mm diameter N42 magnetic ball JB welded to it.
Complete carriage assemblies fitted
close up of the
carriage assembly with bearings fitted
Well I think the design is pretty much finalised so I have started to machine and print parts and assemble them.
First up was the hot end. It was cut from a single piece of alloy bar on my lathe and then the 5 mounting holes drilled on my mill. I still need to machine the stainless heat break and alloy heater block however which is planned for this weekend. I am still tossing up making my own extruder nozzles but for the cost it would be just as easy to purchase them.
cutting heatsink grooves with parting tool
Tapping the M6 thread for the pneumatic fitting and heat break
Drilling the holes using the mill with DRO and the circular pattern function
The next task was to print the end effector on my UP Mini printer. I ended up using the fine print speed, 0.2 layer height and 1/4 fill just so the sockets for the magnetic balls were nice and accurate. I have modded the heat bed on my Up Mini so it runs at 80ºc which stops parts warping. I also used the new Verbatim filament and am very happy with the results. The raft and supports came away from the printed part quite easily.
My design uses six N42 10mm diamter magnetic balls that are glued into the effector sockets with JB weld. It must be said however that this process was harder than expected and if I was to do it again I might use plain ball bearings and magnets in the rods. The reason for this is the magnetic balls are just so strong. Even at 60mm apart then will attract eachother as can bee seen in the video below and if you get too close they will jump out of the sockets and stick together
As you can see as soon as soon the balls are put in place their poles align and if one is rotated, the other moves. This is important to remember before scuffing the magents so the JB weld has something to stick to. What I did was place the magnets and marked their tops with a niko pen, then scruffed the oposing side with some 240 grit emory tape. I was only able to glue magnets at a time however and needed to wait 24 hours for the glue to set before attaching the next ones. I also found I need to wrap the magents that had already been glues with a tissue befoer gluing the next becasue if the next ball to be glues jumped out of the socket, it could hit the already glued ball with enough force to break the glues and knock the ball from the socket.
The effector was prepared by scuffing the socket with emory, drilling some 1.5mm holes so the glue had a little more to key into, then cleaned both the socket and balls with isopropyl alcohol
end effector sockets scuffed and drilled ready for the balls to be glued
Once all the balls were glued, the hot end, fan duct and 40mm fan were attached using M4 bolts and nuts. This ensures a nice stong attachment that will not come loose or flex which will increase the overall accuracy of the printer. Weight wise the complete end effector weighs 135 grams
I have also designed and printed a twin extruder end effector but have not made the hot ends yet. It is the same footprint as the above effector which will make the tuning much easier. I also disigned adaptors for the E3D-V6 hotendsjust in case I didn't have time to make my own. An adaptor was also designed for the singel extruder above. Again the aim here is to make things as rigid as possible.
end effector with 40mm fan and dual coling duct attached
More parts have arrived, including the 6mm alloy plate, carbon fibre rods and the 30x30 extrusion for the frame so lots more to do.
