Bigger castings, melting and making alloy CNC parts with epoxy layer damping

hello friend today we're going to attempt to melt aluminium and cast this z-car plate for the cnc machine it's quite a big casting let's see how we do i've made the fillets on all these sharp corners in here look and it's got five degrees of draft as well so hopefully it'll actually come out of the green sand to make that happen i need to get busy with the sandpaper and then coat it with several coats of paint so it creates a glassy hard surface that sand won't stick to time to dust off the green sand the green sand is quite heavy now this flask here was made especially for this project because none of the others were big enough to say it was a crude construction would probably be generous that mumbling there was me deciding the sand was a bit too dry i did just add some moisture but probably not enough let's plow on anyway the idea of this threaded rod here is to act like a reinforcing bar to help hold the sand up at this point i'm kind of treating this as a test run a dry run as it were considering there's not enough moisture in the sand oh that's actually surprisingly good got some break off in that corner in general though the pattern itself's come out quite clean so it's a promising start let's just add some more moisture [Music] and we're back this time i'm remembering to take the sprue out the casting strategy that you'll see here is i think much better than in my previous videos and that's down to people like cole foundryman check out his channel by the way it's amazing who have given me lots of really useful comments about how i should be gating and pouring and all the rest of it oh we got some at least we'll see how this paw works out but hopefully i can share some of my learnings here the sound still looks a bit too dry but better than too wet so let's go with it on the other side now i'm just placing these raised sections on this part of the pattern and using packing tape to cover over the screw holes and some of the bigger voids those knots there you can also use packing tape like this as a quick and dirty non-stick surface for the runner the observant among you will have noticed the drag the box that's on top at the moment is very thin that's because a flask this size full of green sand gets heavy very quickly so the thinner the better and that's why i've screwed that ply plate onto the bottom there just so that it doesn't all collapse out now as you can see the parting there was very in ideal i guess i didn't use enough parting dust or something but the sand stuck i'm figuring as long as it goes back exactly the way it came out it should still work anyway so i'm plowing on taking out the runner here that was made to be the same cross-sectional area as the end of the tapered sprue so there's no interruption in the sort of flow rate of the molten aluminium and it runs straight down the length of the flask to this spin trap which i'll say a little bit more about if any of this works looks pretty damn good let's make the riser here and i'm going to use the vacuum to actually pull the sand out with this tube or it just stays in there now it's just a question of some intricate spooning to join up the riser that's where the aluminium is going to flow into the main pattern the gate as it were and now it's a question of putting the two halves back together quite precisely using the dowel pins and when i did this i thought it worked quite perfectly but watching again on the video i can see some sand dropping not much though so hopefully we're good it's quite heavy i want to give a massive shout out to my man colin who emigrated to austria and gifted me this new furnace like a boon from the heavens which runs on waste vegetable oil and it just gets much hotter and superior in every way to my old furnace the extra capacity and size means i have to reach in a bit further to do the de-dressing and you can see my spoon wasn't quite at the right angle and also check out my glove it's a bit hot for doing it this way colin also gave me some really nice lifting tongs and a crew support but i'm using my slightly larger crucible and unfortunately the tongs don't fit that so i'm using these rubbishy old ones that i've got here's a few things to note the pouring basin is as close as possible to the corner of the flask this allows the cruiser board to be much lower down and so the aluminium is not splashing down uncontrollably from a great height it seems to be filling slowly and i do wish i'd made the lip between the pouring basin and the top of the sprue a little bit smaller and i think it might have gone a bit better for the next pause i think i want to get a temperature probe going it's quite hard to tell what temperature it's at and i think it sort of looks hotter than it is just because it's getting quite dark at this point a little bit of folded sheet metal around the edge of the top of the flask there where that inevitable fire situation is going on probably would help i want to plug off andreyman one more time i'll leave a link in the description he's got a great video about the pouring technique and how you basically want to keep a smooth consistent flow where there's an oxide layer surrounding the stream of aluminium as it goes down and that so prevents oxide layers being folded into the final casting hmm don't actually know if that's enough oh look at that oh this looks quite promising oh that's absolutely straight unbelievable there we go this has gone a bit funny here there's a bit of a leak but i like that spin trap worked and it's a little bit holy so it probably did cut some goblins see the aluminium somehow went under and floated the sand up interesting yesterday was just a haze of chips flying and chatter and using the mini mill to machine the critical surfaces on that casting i didn't get any of it on film but you can imagine it can't you know i used the fly cutter on some of it that said keeps flying really quickly everywhere this was use the drill as a little power feed back and forth thing with that speed up speed up this is boring whoa slow down too much chatter speed up against vw too much chatter didn't use the power levels get the clamps going oh that's the wrong way round this isn't going to work it's not sitting quite level flip it over let's try it that way first machining those bits now it's almost flat let's flip it back hand wheels back and forth up down up down change the bit change this i feel a little bit silly after my initial jubilance uh thinking this had turned out perfectly it had actually run out of aluminium and my fear about the riser not really filling up seems to have been justified because actually this piece around here especially wasn't quite full which annoyingly meant i had to melt quite a lot of this area back to get it all to the same level what this means is that my linear rail carriages here can't quite bolt where they should bolt as in bolts should go through here rather than cut up this whole casting and re-melt it and do it again shock horror i decided i'm just gonna buy a piece of aluminium to go along there um the rest of it on the whole machine has been either cast from scrap or scrap extrusion salvage from stair lifts or other wacky things but we need to finish at some point this century all right well i've just been putting that together so far i've only just moderately tightly screwed in those bottom ones and up here look at this precision oh you can't see it from around there oh my god it's like the plates are machined they're just exactly on there just look at these plates here how they are just in the right line nicely coplana oh it's gonna be so solid once it's all bolted up okay so now i'm the reason i've done the bottom ones but not the top ones is because i wasn't sure of a precise distance between the holes this t6 6082 alloy is pretty tough but it actually cuts quite well on the table saw if you don't mind shavings going all across the workshop okay the design is changing based on a blunder but let's make the most of it a layer of metallized epoxy being sandwiched between the casting and two new strips of aluminium can actually help damping quite a lot and there's a whole wormhole of constrained layer damping theory that you can go down if you want to but i won't butcher that topic now epoxy is massively strong in terms of sheer strength but peel strength isn't so good the plan is to have bolts pulling the layers together so hopefully it will make a really strong assembly it's a very meaty casting but it definitely does ring like aluminium does but it definitely does ring kind of like aluminium does with a very rough and random surface for the epoxy to key into we're just adding 0.1 millimeter spacers just allow some room for this damping layer now if i wasn't a complete charlatan i probably would have calculated the exact width that the constrained layer should be for optimum damping in fact i did that and the 17 page calculation just happened to turn out exactly 0.1 millimeters the size of shim i had to hand now that's fully cured it's time to go back to the mail and make those bits continuous with the surfaces i already machined underneath just need to draw some holes to mount the guide blocks for that side problem the bolts here that attach the linear guides on to this plate are gonna snag on the ball screw housing as it moves up and down so i need a way to counter bore those and i actually have a counter ball of correct size but the problem is there's no real way to get in there and my 90 degree thing doesn't have a chuck so even especially down the bottom holes down right down there it's going to be very hard to counter bore so what i've ended up doing is drilling a hole in the back of this and threading it putting a little thing in there and i'm going to drive it with that and go through the holes the other side with a hex key and hopefully that's going to work oh piffles now it's snagging on there it's still not long enough in an extension bar for our extension bar ah longer bolt okay now that worked a treat [Music] i'm using the dial indicator here on the slider to try and perfectly center stroke align the ball screw and i had to do a tiny bit of filing down there but it seems to be working just right now we're pretty centered yep that's quite nice it's just to take off the very high spots of the [Music] milling [Music] here's the technique to get the vertical rails exactly square to the y rails at least in this plane so i'll just do that up loosely now [Music] likewise here is the spindle plate it's going to fit on there thus ways and these rails are going to be bolted to the side plates and it's going to go down and up like that there's another half to this pattern sticks out in this direction as well to make it rigid and beefy enough to match the rest of the cnc machine the problem we've got is one of scale though uh that i can't pour enough aluminium at once in the furnace so we've just got a new crucible for that which actually leads to other problems but we'll come to that in a different video the other problem is that this won't sit on the mill it can't mill these inside edges in one pass or even two passes really so that's going to be a bit problematic anyone out there in wales with a giant mill who wants to help me out with this don't hesitate to get in touch um otherwise we're gonna have to work out some other convoluted way of finding very precise edges on these potentially re-indexing it on the mill like a hundred times or casting with metallized epoxy and a straight edge something like that i'm pretty pleased with how this casting came out we'll move on to this one in a different thing just a quick note if you're interested in seeing more on the cnc machine build you may want to check out our other channel flowering elbow for super nerds

Channel: FloweringElbow

Views: 51,933

Rating: 4.9117851 out of 5

Keywords: Flowering Elbow, CNC, z-axis, z axis, casting, melting, furnace, aluminium casting, green sand casting, milling alloy, machine parts, making machine parts, cnc machine parts, diy cnc, large diy cnc, making a cnc

Id: Jh4MVzn61dg

Length: 19min 48sec (1188 seconds)

Published: Tue Jun 29 2021