BigBrain3D - Retractable Purge Mechanism - Install & Test - Chris's Basement

and now we're going to check out the retractable purge mechanism from big brain 3d [Music] hello everyone i hope you are well chris here back again with another multi-material video only this time we're going to tackle that purge block the white tower that wastes a whole lot of filament that no one likes and we're going to do that with a mechanical purge mechanism from big brain 3d and rather than me try to explain how it works i think a video for this is worth a thousand words so let's check out their site so basically what we're seeing here is anytime you have to purge and go to a different color it's going to run over to the side use this purge mechanism to make a plastic bead rather than to have to build the whole tower it's going to dump the bead switch out the color and then go back to printing and our goal here today is to get this whole thing set up and see if it actually saves us some filament so basically we're going to continue on from the last mmu2 video a couple of weeks ago i have a few more upgrades for the mmu2 and things i'm going to change and we're also going to use proper spool holders and one of you in the comments left me a link to a gravity spool holder that i really like let me show you that real quick so basically what we have here is you attach your filament onto a threaded rod that has two gears on the side these are designed to use with that prusa plastic tray i don't have mine any longer so i did print some they are available in this file set link in the description but you put your ptfe tube down here run your filament through then as your mmu picks up filament it backs the spool up then when you retract to put the filament away gravity brings it back onto the spool this is an ingenious idea so if you don't have a filament system already or you might be having problem with the rewinding spools check these out and i am very confident that this new spool holder is going to make my life a whole lot easier during a long mmu 2 print and i am going to print the same model we did in the previous mmu2 video this rubik's cube and we're going to compare the weight of the beads from the big brain kit to the white tower we created in that video just to see how big a difference there might be so let's get started and see what you get in the kit when you order it so here's what you get when you order the kit all the printer parts will go over what all these are when we're building it you get a couple of different screws some sweet stickers some grease some captain tape strips some aluminum tape four springs a thumb tack that has been cut to the proper length and a washer that has a section kit out of it now if you want to build this yourself just print your own parts you can cut the washer yourself they have instructions for it as well as cut down a thumb tack and cut your own captain tape and you can get aluminum tape pretty much anywhere but the kits are only 35 bucks and it's a really ingenious design so definitely consider grabbing yourself a kit rather than printing it yourself just to help the company out they've done some of the more tedious work for you like cutting the tape and the washer just consider that when you're looking at purchasing one of these so the first thing we're going to do is take our thumbtack that's been cut down and we're going to put one of these captain tape pieces on the back of it these are about 50 millimeters in length if you have to cut these yourself we're just going to put that across the back of the tack somewhat centered leave about the same amounts on both sides then we're going to take our catcher piece and the pin part of the thumbtack is going to go in this hole we need to fish the captain tape through the back here you can do that with pretty much anything the captain tape will stick to but we'll just fish it through make sure that tack is in the hole then we'll flip it over and just lay that tape right down on the back just like that to make sure the tack isn't going anywhere then we'll take our cut washer with a pair of pliers and we're just going to slide it in these grooves right here above that tack it sets in there just like that this is actually where the nozzle is going to come to make that bead so that's why we have these metal parts next we'll take our main bracket and our pivot arm and it goes in this hole right here make sure it turns freely we might put a little grease on that before we get the whole thing together then we'll take our foil tape on my cutting mat here and i'm going to cut a five millimeter wide strip and we're going to wrap it around the end of the flicker arm right here again we're putting the tape on just so it's a little more heat resistant just like that now we're going to take our wedge piece our connecting arm our assembled catcher and our flicker arm and put them together your wedge piece has this little part that sticks out on one side that's the side that your flicker arm goes in just like that then your connector piece will go down opposite the wedge piece just like this and the whole thing will go on your catcher arm right here now we'll go back to the base and get some things assembled we'll go ahead and put some grease on our pivot arm we'll thread our catcher assembly through the bottom of the base just like this your wedge will fit down in here in this base section and then we're going to put a screw in from this side it looks to be around an m3 by 12 cap screw it'll go right in here and then thread into the wedge printed part just like that and now we want to make sure that our mechanism is turning freely you should have it where the flicker is down and when you pull out that's going to help eject that piece this is where it catches then it kicks it out just like this then we have our pivot arm it has an open loop that goes on this side and then there's a closed loop that goes on the bracket post and before we put it on it goes in this hole right here it has to line up with our catcher arm and our action arm up here so it'll need to go in this hole it's down here at the bottom and then this tab on the top will have to line up with the divot in the action arm then we can press it into the mounting hole just like that so make sure both of those are in the correct place before you put it down and then from the back we're going to use our other m3 by 12 cap head screw to attach the pivot arm and with that attached now we can put our springs on these posts these two will go on this post these two over here will go on this post i'm just going to force them on with my o-ring pick first two are on and the last two are on and the whole mechanism should move just like this before you put it on your printer you might want to work it quite a few times maybe 100 times or so just to make sure everything is moving freely and it doesn't get hung up and then we need to put our cage piece on i totally forgot to film this while i was just doing it but it slides in this groove right here it needs to be flush right up here in the front i did have the tap line on it is pretty tight here's what it looks like from the top and then we need a piece of aluminum tape that goes right here i'm going to cut out a 10 by 20 strip and that's going to go all the way in here to the flat spot on that washer about like this and then we'll fold it over to the outside and then there's a little divot in here i'm going to work it into that divot with my own rig pick it should look something like that and then we can put a little bit of our grease on any of our moving parts the pivot arm up here here in between on the action arm down here on the end of the pivot arm this side of the catching arm and we can deploy it put a little on this side anywhere where there might be just a little bit of friction on those printed parts we'll put a little up here on the connector piece as well that seems to be one of the places that it really likes to catch we'll clean it up a little and it seems to be moving pretty freely and it's ready to go we're ready to put it on our prusa and on the printer we're going to remove our right z nut just these two screws on top here then we'll take our mount piece and use those two screws that we removed from the z-nut like so and then we'll put it right back on that z-nut it'll set just like this and we'll screw it back down then we're going to take the screws off of the left z nut and we'll use those two on our cap piece to put that on the left side just like we did for the mount on the right side it goes back on just like this now the cap is on the left side and now we're going to take our whole mechanism and the two countersunk screws they gave us in the kit and we're going to put it on the mount over here on the right side and our install is complete but now you kind of get the idea how this is going to work when you want to change color the extruder housing goes all the way over here hits the action arm makes a bead of filament lets it loose kicks it out the front now one of you in the comments mentioned that there was a replacement front ptfe holder this part right here and i do apologize that i didn't catch this in the last mmu 2 video this original one does seem to be working just fine but i want you to have the most success possible so i'm going to go ahead and replace this we will have to remove this motor and selector again so if you need to do any maintenance now is a good time to do it but this is what the new part looks like the features are probably just a little bit sharper so you have more success of being able to clip accurately just something to look into this part is available in that same part set in the description of the last video i'll add it to this one as well but if you're having problems where it's not cutting it's just pulling the filament maybe consider upgrading to this part this one looks to be marked r2 so i'm pulling these three selector motor screws out one more time i'm going to slide this whole thing out and thread it off of the selector then we pull the rods and pull the selector and then it's just these four screws to remove this part all five of the ptfe tubes will probably come with it just swap these back in to the new part make sure the flange side of the tube is facing out so facing out this way all the ptfe tubes our parts ready to go we'll just slide the new part on and put our screws back in then we can just put everything back together while i have it all apart i'm going to go ahead and replace my blade as well these are standard nine millimeter snap off blades you can buy these pretty much anywhere so the hardware part of this is complete and i'm going to say that was probably the easy part of this whole setup now we have to make some changes in the slicer so that it will actually actuate that arm when it wants to do a color change so let's see what we got to do here to make this thing work so we will get all that slicer set up in a minute but big brain 3d has given us some tests we need to do to make sure the nozzle is in the right place to do the purge you have a purge location test then you have a purge blob test they would like you to do the blob testing 500 times in a row to make sure you have everything set correctly then they consider that to be a go forward solution and then you can start your prints so let's just download these two g-codes see what's in there and see what we need to do to line up our mechanism so here's the purge location test g-code this is the one we need to do first basically what this is going to do is tell us if we're in the exact center of that tack with our nozzle because that's where you need to be before you do your purge now i didn't have a lot of luck running this g-code so i'm just going to do it by hand line by line and that way i can show you what it's going to do as well so let's just open up pronterface and we'll connect up and the first thing this g-code wants to do is just home the x-axis so let's do g28 space x so we've home decks now it wants to lower the motor current with an m907 we can do that and then we're going to move x to 200 to get in position g4 is a pause we don't have to worry about that now we need to depress the arm so we're going to move all the way to 250 but we need to raise the z before we do this if you do run this g code make sure your z is at a certain height so i'm going to go ahead and raise mine up now that we're all the way up i'm just going to zoom in on the mechanism because that's what we need to see next so now that z is up let's move to 250 that should engage the mechanism and we did partly then we want to move five and a half more millimeters this is the one that you need to adjust so let's go ahead and do the recommended first 255.5 the mechanism is engaged but the question is is that nozzle in the center of the attack and this is going to be really hard to see so i'm going to draw a line where the center of that nozzle is so you can kind of track that silver spot as we move closer to the mechanism so if we go to 255.5 like it states in the g code we are actually a bit to the right of the attack we need to be right in the center so let's click back a millimeter that looks better we'll go back a tenth three-tenths i think that looks a lot closer to the center of the attack and if we do an m114 we are currently at x 254.2 so in this g-code we want to change this line and i'm just changing it for reference we'll use this number in the next g code so i'm going to save that so now i'm going to start again g28 x i'm going to lower the current to 450 i'm going to send x to 200 then i'm going to send it to 254.2 and once again looks like our nozzle is really close to the center of the attack so we have a good number now we're going to take a look at the next g-code the actual blob test so we're doing a lot of the same thing we're homing x lowering voltage moving to 200 then to 250 but our new number is 254.2 then we're turning the fan off we're setting extruder to zero we're purging cooling the blob turning the fan on full blast that's the part fan waiting 12 seconds turning fan off backing the filament up and then moving x out and on this second change down here we actually move out a bit to 240 and then we come in a little further than even before we were at 255. this one is 256. so i'm guessing what it's doing is coming in as far as it can to allow it to give it a little more snap so maybe they'll kick out that bead i think that's too far let's change this one to 255 5 we might have to tweak it a little bit but we'll start there and they want you to repeat this 500 times so let's just save it to our sd card and run it once for now and see what happens you will need to go ahead and preheat your printer because this g-code doesn't do this it doesn't do anything but move x i recommend you leave your gantry all the way up i'll pan the camera back up here in a second we're going to start that g-code also i'm going to load just some cheap filament i have to test it out you can either do this with your mmu-2 on a single filament you can load it by hand or you can just unplug your mmu2 and do it in standalone mode and that's what i'm going to do for now it just makes things a little less complicated so i have the communication wires unplugged from the back of my mmu2 and i'm just going to undo the bowden tube and feed my filament into the extruder by hand and before we start the print big brain does recommend that you turn off crash detection because we are colliding into that mechanism so we'll go to settings and we'll make sure crash detection is set to off so our gantry's up we're up to temp i'm going to go ahead and start this g-code here goes nothing if you get a warning about filing complete go ahead and say yes we're going home we have triggered we are making a blob we're cooling the blob but we did not clear the blob so it looks like the split washer that's on top here is having a hard time releasing the nozzle it's actually spinning just a bit so i'm going to put some aluminum tape on the back to try to keep it in place so that bit of extra tape there on the top and the back of the washer should help a bit let's go ahead and give it another go we'll start the g-code once again we are making a blob and it did kick the blob out that time so let's try it one more time here restarting the g-code once again making a blob we are cooling said blob and it kicked it out so now they want us to test this 500 times so let's jump back to the computer so i'm pretty happy with my code because we are able to kick those blobs out but we want to make sure that it's going to work during operation we don't need to g28x every time so i'm going to omit that line for my copy but i'm going to copy everything else we'll copy and then basically you're just going to paste it a bunch of times there is probably a plug-in that will do this for you but it's not that hard to go ahead and paste it just remember we have roughly 30 lines you can just keep hitting ctrl v so 30 times 50 we're just going to keep pasting until we see it get to about 1500 you can just hold this down and it'll keep pasting continuously it took about three seconds to do there's line 1500 now we'll save this again put this longer file on our sd card make sure your z is up and you're still preheated and let's just let this thing run so far so good we're just going to let this thing run i'll spare you the 500 runs we're going to do i'll give you an update here in a few so so far so good it has missed the bowl a few times but i think we've done about 40 maybe close to 50. we'll just let it keep running see if we can get through all 500. so i've now run our g-code about five times remember we did 50 on that so i'm going to do a total of 10 or maybe more and things have gone pretty well i've got a lot of beads but i've had a few failures i highly recommend that you reprint the gate piece and the catcher piece you might actually want to print a couple of these because i think they're going to need adjustment as you tweak this whole mechanism make sure your foil tape is nice and laid down i did break the gate on this but it is still functioning i also glued the top washer in place with a little bit of super glue it might be a good idea to go ahead and glue that tack as well but so far so good it's hanging in there with the captain tape but where that washer is in the catcher arm it sets right in here i just put a little dot of super glue to help keep that washer in place because it was kicking it out occasionally but so far so good i'd say we were about 85 successful at this point we'll keep testing okay we have done it 500 over 500 blobs have been printed now i have a few tips so i already said make sure you print some extra parts especially the arm and the fence you might want to consider gluing that washer the one that's on top because it does tend to move around and then on your tack you have captain tape that holds it onto the bottom of the catch arm that captain tape is to give you just a little bit more protection from the filament being hot when it makes that bead but as you probably know filament likes to stick to captain tape so that can keep your bead from kicking out so i recommend just finding something like a q-tip or even just a toothpick and taking just a little bit of the grease that you put on the rest of the parts and rub it on the top of that tack because not only does it like to stick to the captain tape when it's cold when it does its first blob it likes to stick on that tack every other one after that after the tack has been warmed up works just fine but just that little tiny bit of grease breaks that contact and it'll start working when it's even cold so those are all of my tips after you have it lined up and you start running through all this test g-code everything starts to pan out eventually i'm pretty confident now that it can make a blob no matter what i did also test taking one of the springs off of here because it was kicking the beat out quite far but then it didn't seem to be kicking it out enough so i still do have all four springs so now i'm going to go ahead and hook my mmu-2 back up then we will go to the computer get us a test file and get the slicer set up ready to go to do a test print and i'm just going to download these cubes that i like to test with it's easy because they're quick prints and you get to see a lot of filament changes i'm just going to pull three of them in for now just for testing purposes multiple objects yes now the first thing we need to do is turn off our purge block here so we'll go to print settings multiple extruders and disable wipe tower we'll go back to the platter the wipe tower is gone and then we are going to paste in our pretty lengthy tool change g-code here they have for us so we'll just start at this curly bracket we'll get all of it copy all the way down to here head back to prusa slicer and then in printer settings we'll go to custom gcode and this box right here is tool change gcode and we'll paste that then we will go back to their site it gives you some tips on filament shaping but it is pointed at pla so if you need to change to a different type of material this is some settings you can use to do that and then we're going to copy this section of gcode this is going to go in our start g code this first one up here at the top and it's going to replace our priming line and we're just going to start here at this if statement and select all the way down to this last g92 and paste in the new start g-code this g-code should create the priming blob we might have to tweak it a bit just to see how this whole thing is going to work but we're going to start here and remember if you made changes to run that test g code like we did before when we were just testing the blobs we made changes to the x position they need to be made in your tool change and if you're using the start g code as well there is change this line for you so you know which one to change my final value the one i liked the best was 2 5 4 6. it gets me right in the center of the attack i need to make those changes anywhere it says change this line the first one 2546 that's purging the after tool change purge g-code 2546 right here and then the third one two five four six this is the extra movement where it tries to remove the blob and then your start g code the first one is right here extend arm two five four six and then down here for that second hit just don't forget to make those updates so we're going to go ahead and slice and get it put on our sd card and then we can start testing so here we go i'm going to preheat then i'm going to go ahead and tell the mmu to load all my filaments because i always recommend you load your mmu2 before you start using it just to make sure everything's set and it'll work all by itself i'm just going to load one two and three for this test my three filaments are loaded i'm going to unload my test yellow filament and now let's start our test print now for some reason with this g-code it's wanting me to remove old filament first i don't know if that's something in the start g code or the tool change g code but i'm not going to do it i'm just going to go ahead and hit the button and it resumes okay so let's see where it goes from here so we've leveled we've moved over to the mechanism so we can prime with a blob now it's loading filament one now it didn't make the priming blob after it did filament one and the nozzle hasn't been primed so that's not good so i think i'm going to change the start g-code back to the regular prime line so my start g-code i'm just going to go to the default mmu2 printer configuration and i'm going to grab the stock start g-code copy it and then in my big brain config i'll just select all and paste over it we'll just go back to the prime line for now i'm not sure what's going on why the mmu doesn't like that prime blob like we're trying to do but let's try this and see if we can do the filament changes with the blob definitely had to switch to a lower profile catching tray maybe like a cookie sheet or something would be best for this this time it loaded one and we're doing the prime line so it should go straight to the print from here and then when it does the tool change g-code it will make the blob now we're going to do our first blob it should make one for filament one it's unloading filament one now it's loading filament two it kicked out the first blob it should be making the one for the second one it's cooling the second one and it kicked out the second one we kicked out our next blob we're creating the first one for filament three and we kicked out our filament three blob so we've successfully changed three filaments let's let this test run and just see how it goes so the test print is complete now i did have a few issues with the filament loading but that's mostly because of how i have the filament set up here all the purges went great it made all the blobs just fine so i think we're tuned in on the purge mechanism and we're ready for a larger print so the testing is complete and the purging mechanism is working as intended we went through that whole test print and no issues at all making those blobs so now i think we're ready for a larger print but i do have some concerns the first one being with purging volume traditionally if you needed to go from a darker color to a lighter color you could increase the purge volume so you didn't bleed into the next color like if you're going from red to white that white is going to be pretty pink unless you increase the volume and traditionally that's done on a white tower with this scenario you would actually have to do multiple blobs to get that amount of purge volume to be able to clear the color correctly i'm not sure how that works right now but i am going to investigate that later also with the filament tip shaping currently we're doing that in the g code the one that we assigned during the tool change earlier i would really like it to have it do it by the prusa slicer settings and there is a python script out there for that so i am going to try that as well but other than that let's go ahead and move to the larger print and just see how this whole thing's gonna turn out [Music] [Music] so that didn't go at all like i wanted it to i made six attempts at this cube i have many many hours invested in it and the one that you saw in the time lapse was the best that i could do but before we take a look at it i did want to thank big brain 3d they did support me through this whole thing they were very responsive but even with their help i couldn't get a successful print and also sergio over at hvac a to z he sent me this kit to try free of charge so that was much appreciated so let's take a look at what the mechanism looks like right now you'll notice that it looks a whole lot different than when we started that's because i broke it roughly four times and it seemed to be all for different reasons and the reason why it failed the last time was because it broke one more time i had to replace the pivot arm i broke the tip off of it i broke this catcher arm twice one because it was stuck out when the z went down and snapped it off and i also broke pretty much every one of these gate pieces that i put on this one is broken as well and each time you make a change to this mechanism you have to switch out a part you can't just try again you're going to have to go through that sequence again to be able to tell where the nozzle is relative to the middle of that tack because not all of these parts are going to be the same depending on how you printed them what printer you used so if you get a failure in the middle of a print you can try to replace that part but most of the time you're going to have to start from scratch you'll also notice that pretty much every spare gap on this printer is full of these little plastic blobs this even caused me to fail z homing once you can see all of them collected back there in the extrusion as well and here's a look at the final print the bottom bracket on the catcher arm actually broke and caused the printer to skip and since you have to turn off crash detection you can't recover from it you can see where it skipped and tried to continue printing it just didn't work out one thing i did notice though when using this mechanism versus the wipe tower just take a look at the pink filament you can see how much darker this one is versus the one using the mechanism it actually does a better job than building the white tower at purging from filament to filament so that is one positive here i did notice that when it was doing all this operation it would actually make two beads every time it swapped so that helps get the filament clear so i really do kind of like this mechanism it's fun to watch i think it's really interesting and i think there are advantages to it over the white tower especially when you look at the color bleed on both models but the big question i had if it did work successfully would it save you plastic and i think we can still kind of get an idea about that so our finished print doing the wipe tower weighs 98 grams our roughly three-quarter finish print from the mechanism weighs 80 grams so we don't have to get too scientific on this let's just call that roughly 80 percent of the amount of the whole print if you weigh our white tower from the complete print it is 254 grams and if we weigh all the beads and extra filament that we created during the mechanism print we have 186 grams and let's be honest a lot of these fell on the floor or got stuck in the printer some even fell inside the print that's kind of another disadvantage you can see a picture i took when that happened right here the blobs have a mind of their own and land on the print bed or wherever they might want to land but just take that into account even if this was 20 grams heavier it's still a lot less than that wipe tower so i do think it saves you filament so i did really want to make this thing work i watched it for hundreds of hours through multiple prints and it would go just fine for eight or nine hours at a time but it seemed like as soon as you turned your back on it one of the blobs would get stuck on the arm or something would break and you'd have to start all over from scratch because there's just no failure relief here and having the crash detection off makes it even worse maybe if you could leave that on you might be able to recover from some of these issues but still not all of them if you don't have it set up just right and the right tolerance on your printed parts you're never going to be able to get that consistency through these hundreds and hundreds of filament changes like on some of these multi-material prints it was a lot of fun to test and i do appreciate big brain 3d their ideas and their support but i don't think this one's ready for prime time just yet i hope you liked this video if you did please let me know in the comments and i will see you very soon on the next one no more multi prints for a while i can't handle the stress

Channel: Chris Riley

Views: 11,675

Rating: 4.967936 out of 5

Keywords: 3D, printer, Printing, 3D Printing, 3D Printer, ChrisBasement, ChrissBasement, Chris'sBasement, Chris Basement, Chriss Basement, Chris's Basement, ChrisRiley, Chris Riley, benchy, 3dbenchy, 3d, Big Brain, filament, duel color, wipe tower, purge block, MMU, MMU 2, Prusa, color, multi color, Multi Material

Id: V4u0UnHD9Tw

Length: 38min 24sec (2304 seconds)

Published: Wed Oct 14 2020