I Turned PET Bottles Into A 3D Printed Pi Case - DIY Bottle Recycler

a few weeks ago I published a video on a controller that I designed for a pet bottle recycler I've now completed the rest of the components and at the end of the video I'm going to use it to turn a few old pet bottles into a new case for my Raspberry Pi let me start by saying that the concept for this design is not something that I came up with there are a number of other designs for these devices available online already I like the concept but couldn't really find one that suited my needs so I decided to make my own so here it is my d bottle recycler which I've named pet or pet to print there are four main elements to the recycler starting with the bottle side we've got a cutter which cuts the bottle into an even width continuous strip then we've got the hot end which the strip is pulled through to partially melt and converted into the size and shape for filament then there's a reel which pulls the filament through the system and stores it for printing and lastly is the controller on the front which controls the hot end temperature and the reeler motor the device doesn't fully melt the p strip it just softens it enough to be folded over into a cylindrical shape this is the same diameter as common 3D printer filament I started out by 3D modeling the design in Fusion 360 I designed all of the 3D principal components and modeled some of the main B out elements to get the general shape and design right then came a lot of 3D printing I printed the parts out in petg for added strength and I had to make adjustments and redesign some of the parts until I was happy with the them with the parts all printed we can start assembling the recycler we'll again start on the bottle side with the cutter there are two main 3D printed parts for the bottle cutter the base which holds the cutter and the bottle support and then the guide which just keeps the strip in the same orientation through the bearings when feeding into the hot end to join the two pieces we need to add some M3 brass inserts onto the side of the base we'll melt these into Place using a soldering iron before we screw it into place we'll need to add the cutting mechanism the cutter uses two 608 ball bearings to cut the filament these are really cheap and easy to get as they're the same size bearings that are used for skateboard wheels and fidget Spinners to turn them into a cutter we need to sharpen one face of each bearing I did this on a bench grinder to make sure they're kept Square we then need to epoxy two M8 studs into the Bas to mount the bearings on while we've got some epoxy mixed up I'm also going to epoxy the 8 mm shaft into the Reel holder to use later with the epoxy cured we can mount the ball bearings onto the studs we also need to add a metal strip underneath the bearings this stops the sharp edge of the bottle from quickly wearing out the printed base a small washer is used under the first bearing with its flattened or ground face up so that it doesn't rub on the base a nut then holds it in place on the top we then add a nut to the second stud then the bearing with the ground face down this must be just at the right heart to contact the face of the first the nut then holds the second bearing firm against the first bearing and the nut below it we can then screw the guard onto the front of the base with some M3 button head screws to finish it off let's also add a M8 stud for the P bottle stand this will hold the bottle upright to feed the end into the cutter it's held in place with a knut and washer on each side and that's the cutter complete and ready to be mounted onto the stand the stand consists of two sections of 2020 aluminium vslot Extrusion and and two sets of legs one on each end these are mounted with some vslot nuts and M6 screws we can add the legs onto one end and then slide the cutter into position next let's assemble the hot end this is a really simple part of the recycler but actually turned out to be one of the more tricky ones to get right I'm going to skip through this initial design because there were a couple of things I didn't think through when I designed it and it didn't work at all because the nozzle is going to be over 200° C we need a way to stop the heat from reaching the 3D printed plastic holder I thought I could use the heat brake on the current hot end assembly but I overlooked the fact that this meant that the strip wouldn't fit into it so it was back to the drawing board shortly after finishing it now next let's move on to the most complicated part of the recycler and that's the reeler this is a part that's driven by a steeper motor to pull the filament through the cutter and the hot end we'll start by making up the Reel this is something that I've changed up quite a lot from the others I've seen online on most other machines The Reel is fixed on both sides and you need to pull the filament off the Reel once it's done I wanted to avoid this I made the Reel removable which makes it easier to get the completed filament off afterwards to finish off the Reel we need to melt some m2.5 threaded brass inserts into one half of the reel for the opposite end to screw into this is split to make it easier to 3D print without supports we also need to add some inserts to The Reel holder for the small catches that hold the reel in place when it's running we can then screw these parts together with some more m2.5 screws to finish them off next let's press another two 608 size B earings into the real stand one on each side we'll use an 8 mm shaft as a guide to keep them align now we can mount the motor on its holder using four M3 button head screws then we can Mount the base onto the top of the vslot Extrusion and the motor hold on to the underside The Reel is driven by the motor through a belt and pulley system on the back so we can push the re shaft through the base with a spacer between it and the bearing then add another spacer on the opposite side we then add a pulley to finish it off and the grab screw holds it in place a second pulley sits on the motor shaft with a belt connecting the two the belt is tensioned using the relative movement between the re base and the motor holder pulling them further apart puts more tension on the Belt now that we got the mechanical Parts in place we need to add the controller if you watch my video designing and building the controller I ended that off by saying that I wanted to make it a bit more compact it it was designed as a shield for an Arduino Uno but using an Arduino Pro Mini we can make it much smaller so I designed a new PCB that swapped the Uno out for a pro mini and I brought the components a little closer together PCB W then made them up for me in the same color scheme as my previous Shield I then solded the components onto the PCB starting with the smallest and working towards the largest with Arduino going on [Music] last I also 3D printed a housing for the controller but before we put it into the housing we need to program it and set up the steeper motor driver's current limit to upload the code to the pro menu we'll use a USB programmer we just plug this into the pro menu and then into a computer to upload the code to it to set the current limit we need to measure its reference voltage using a multimeter I'm using my pocket Pro multimeter with clamp leads we'll then adjust the limit using a screwdriver to suit the rated current of the motor in my case this is the same as the maximum current for the driver so I'm aiming for a reference voltage of exactly 1 volt once programmed I found another issue when running the steeper motor it sounded like it was intermittently skipping steps or stopping and this seemed to get worse if I sped the motor up I put the pocket Pros oscilloscope on onto the output and found that the uino stopped pulsing the motor for brief periods of time this caused the driver to stop turning the motor in working through the code it seemed like this happened each time the display was being updated so it looks like the uino takes longer to update the display than the period of time between the pulses so it just stops pulsing the driver while finishing updating the display this is obviously not going to work when we need a consistent pulling Force so I tried making the display Loop a bit faster but in the end I had to modify the code so it no longer updates the display when the motor's running this does limit the feedback on the display during operation but it won't affect the overall design or functionality I'll have to investigate whether I can make the display or at least portions of the display update more quickly in future in any case we now get smooth Pulses from the Arduino and a consistent motor speed so let's get the board installed in the enclosure first we need to add some M3 brass inserts into the bottom to screw the PCB to the PCB is then held in place with some nylon standoffs which double up as a means to hold the front cover in place I'm going to glue the OLED display onto the inside of the cover with some hot glue it then connects to the PCB with a short ribbon cable we can screw our elements and thermost into the terminals plug in the stepper motor and then close it up with some M3 button head screws the 3D printed knob gets pushed onto the rotary push button and we can then mount it onto the base with all of the components in place we can install the second set of legs to close off the end of the extrusions now let's get back back to the hot end as mentioned earlier the device makes filament by softening a strip and rolling it over in the hot end to form a cylinder this means that the strip needs to start being heated right from the time it enters the hot end or it'll be too difficult to pull through so I redesigned the hot end holder so that the strip passes through the holder and directly into the heat block we can start assembly by preparing the heat Block in nozzle the nozzle is a standard 0.4 mm nozzle so we need to First drill that out to the filament diameter we're aiming for 1.75 mm but the filament expands a little after it leaves the hot end so we'll drill it out using a 11/16 in drill bit this is just under 1.6 mm the back of the heat block has a small hole for a heat brake we're going to open this up with a taper drill bit so that the outside is slightly larger than the strip width and the taper will help gently fold the edges over until we reach the nozzle diameter we can then Mount the heat block onto the holder the plywood plates act as a heat brake in this design so they stop the screws from melting the plastic holder I've used some m3x 40 mm buttoned screws and these go through the heat block and the nuts hold it into place we can then reattach the terminals and we're ready to try it out to run it we first select the target hot end temperature I found that 215 to 220° work well with my bottles we can then select the motor speed and I found 22 to 25 work well these are just random units they don't relate to RPM or anything like that we then turn the motor on or off with the last menu item now we just need a bottle to turn into filament to prepare a bottle we first need to remove the label and residue as well as any date markings I found that acetone works well for this the cutter works best on a smooth surface and most bottles are rippled in some way you can smooth them out over some heat with a drop or two of water inside the bottle to pressurize it we can then cut off the end of the bottle and feed it into the cutter we can then use some needl nose pliers to feed it through the hot end which is now preheated to 220° cus and then feed it onto the Reel The Reel has a small hole on one of the spokes which we can feed the end through and TI off finally we can turn the real motor on to start pulling the filament through now we just wait for it to turn the bottle into filament you can also do the bottle cutting beforehand to reduce the load on the motor you'll then just feed the strip through to the hot end once the bottle has been converted into filament we can transfer it from The Reel over to our 3D printer to try print I'll start by printing a Ben and calibration Cube so you can see how they turn out there's a bit of adjusting to do on the first few prints as the filament is not quite a solid 1.75 mm section as it's Hollow in the middle I found that increasing the flow rate to about 135% gets good results I print with a bed temperature of 70° and a hot end temperature of 260° once I had the settings right I was actually pleasantly surprised by how well this filament prints the calibration Cube came out looking really good the Beni showed a few signs of stringing and a little undere Extrusion in places but it's also really good for homemade filament it's obviously not as consistent as Factory produced filament but it's definitely usable for home projects so I then converted a few more bottles so that I could 3D print a case for my Raspberry Pi this came out really well too but highlights one of the drawbacks of this process you get about 6 to 7 m of filament from a 1 L bottle but with the hollow sensor and having to increase the flow rate to compensate it gets used up quite a lot faster than standard solid 1.75 mm filament it's also messy to store on the filament holder as it doesn't like being coiled up to print my standard P case with no supports I need 25 M of filament and this is with a really low info density and only two walls so I need to swap a new roll of filaments onto the printer five times for a relatively small print this is manageable if your printer has a filament run out sensor but it's still a bit of a nuisance the case Body also came out quite well with just a little bit of stringing and again some undere extruded areas but with the partially transparent walls and they in full visible it's really not obvious I even used colored Mountain Dew bottles for the 3D printed side panels as well what do you think of the completed case it's really cool to think that this was one's five Coke bottles and two Mountain Dew bottles it also looks really cool in the dark as the RGB fan illuminates the body of the case overall I'm really happy with how the recyclers has come out there are a couple of improvements I'd like to make to it like getting the display temperature to be able to be updated while the motor is running and maybe designing a spool mount for pre-cut bottle strips instead of just having the bottle cutter let me know what other suggestions you have to improve upon it in the comment section below I'll put the design up on my blog if you'd like to build your own and I'll put the code up on GitHub if you'd like to have a go improving it and there's definitely a lot of room for improvement thanks for watching please remember to like this video If you enjoyed it and subscribe for more Tech in electronics projects tutorials and reviews

Channel: Michael Klements

Views: 15,416

Keywords: PET Bottle, 3D Printing, Arduino, Arduino Pro Mini, Arduino Pro, Arduino Uno, Minima, WiFi, PETG, Filament, Mountain Dew, Solo, Bottles, Filament Recycling, Recycle, 3D Print Filament, PET2Print, Bottle Cutter, PCB, PCBWay, DIY, Maker, Tinkering, Electronics, Stepper Motor, Pokit Pro, TMC2208, Hotend Controller, PWM, PID, PID Control, Coding, Gerber Files

Id: CCu6We86dp0

Length: 18min 18sec (1098 seconds)

Published: Thu Oct 12 2023