I think two of the most interesting threads I've seen in ages have both been in the last two days and both courtesy of you Brian. Amazing work, even from somebody uneducated and looking in. I'm sure it's even more impressive from the people who know how much time and effort this all takes, I can only imagine
Tom, Im uneducated too so dont feel too bad. lol It all started when I was about 8 with a Briggs and Stratton engine and it all kinda went from there. Everything I know to this day is solely based on R+D. Moreso the R and about 15yrs of it Glad you liked the F1 Head thread, it was all so ''mysterious'' in there and casting info so thin on the ground as I just had to explain it all. Brian,
Damn... This is beyond epic. Such an amazing work. Really nice skills man! Looking forward to see the rest.
The above is a walk in the park to be really honest. It gets a little gritty now but 'hopefully' I can explain it good enough so that everyone will get the picture and keep reading! @Burni, thanks, that explosion still cracks me up!! Right then, onto the curved runner mould/patterns. As mentioned this is semi complex and not the type of mould building or casting patterns you would normally see on the net. I suppose its for good reason, most casting jobs you see done are just two piece moulds like in the first pair of runners I cast at the start of the thread. These are real easy do, and easy visualize for a lot of folk wanting to make manifolds/parts/and so on. Just top and bottom mould and you're done. I started with those for good reason and not the plenum end as hopefully they will provide enough intro to make the next one easier understand. As I said earlier, this part contains interlocks which cannot be designed out due to the nature of the part shape. I will try explain that below with a few terrible drawings of why this mould need to be as complex as it is - hopefully then you will be able to visualize the purpose of the various mould components as I make them - and how they will go together. Below is the cross-section drawing of the part, rotated a bit, with the mould box drawn around it, The rectangles sticking out each end of the intake piece are needed to hold the cores in place like the first patterns you saw me machine earlier. Now....If you were to pack the sand into the top and bottom box around the pattern above you would not be able to ever take the pattern out of the sand as there are undercuts at the flange areas. You would ruin the mould trying to get them off. Below is an image of the sand moulds removed from the boxes. The undercuts areas are highlighted below in red arrows, hopefully you can now see why this would be a bad idea, and not work at all lol Another thing to also notice is that you have no parting line at the thickest area for the fill gates(metal entry). The gates have to be on a joint(parting line) so that their shapes can also be formed in the moulds. Ignore anything in the drawing that looks out of place - its just for visual description, So...a different plan is needed as you can probably guess. What is needed is a collection of sand parts that all fit together to form the 'void' within that you need. You also have to incorporate your gates, sprue(fill tube) and risers into this collection of shapes. The general idea is to make each shape contain no undercuts, interlocks, or negative draft angles. Generally, if this is your 'thing' the shape of everything will come to you with a BANG - you will either see it fairly right away, or you wont ever see a way to do it. As stated - I didnt bother to draw this in solidworks as the design is too basic, but solidworks will only bring you so far even if you did. It will show you the interlocks, and undercuts, but you still need to know where stuff should go in terms of gates, where you can allow part lines on the finished part and so on. So below is how I broke it up, The piece highlight in red is fixed into the top mould - once filled with sand, two screws are removed, the box is removed from sand, and the insert removed from the sand mould. All the other pieces are just collections of sand moulds built together to form one main mould. Like so, Obviously a bit of inside out thinking is now needed since the boxes needed to make the various shapes in the sand parts above need to be in reverse/negative...they also need to contain location bosses for accurate building, and of course the gates, risers, and sprue shapes.... Which will look roughly as below, You are probably wondering by now(if you haven't closed the thread!) about the apparent locking point highlighted within the circle below if you were to lift the sand straight up out of the box, Very simple....its just lifted out at an angle that follows the angle of the fillet within circle above where the runner meets the section over the valve cover... If you are totally lost at this point do not worry....once you see the mould boxes getting made, and the sand shapes they will create all the above will become perfectly clear. Speaking of which...heres the first bit of 'woodwork' concerning them, Back to this drawing again, all of the large bits you see facing you get cut out of 18mm MDF. MDF is horrible stuff and Id normally take from birch ply. Since the budget for this project is running at a shocking 15euros already at this point - MDF will do. I cut this on the cnc with good extraction as MDF dust will kill bearings and slides fast otherwise, (and possibly me too) This is the section with flange/outlet on the same plane. Its used to cut the various parts needed to form those end shapes, the runner curves off 44mm as mentioned - or half the bore center distance to place runners between sparkplugs, spot the draft angle on sides of twin port pattern pieces...and machining allowance... The MDF sides cut out, the small insert piece omitted as I was late taking this photo - there are two identical sets of sides obviously to make each 'side' or end of the boxes... Here is the small piece already fixed to some other pieces to form the walls of the insert box, Below is a shot of a bit of Brazilian Mahogany, I cut out the core print half moons the lazy way. I should probably buy some dowel and half it but this is just faster... These pieces along with one flange piece get built into the insert mould box...the accuracy of placement of these is critical, and although wood - all this mess you will see in the next while is accurate to .25mm. Poor shots - better ones tomorrow, You can see the location now in ref to the other side pieces, same as the original 2d drawings above.... You can now see when this is filled with sand, the sand will take the negative shape needed to form the outer lower flange portion of runner. There are a lot of parts to go into this box yet but its pretty easy to be honest now that all the main 'things' have been located and figured out. Ill take better shots tomorrow eve of each box as I go so you will have a better understanding of what they look like. I hope the above makes some sort of sense, the post went a bit long winded but anyways....the bottom line is, pattern makers and mould tool designers are all a bit cuckoo. Brian,
One of the most interesting and informative threads ever. Similar things to what I come across at work, but with wood and sand instead of tool steel and hot plastic. Most of my stuffis simple 2 part moulds as usually we can just split parts up into smaller ones to eridicate undercuts, do sometimes have to use a slide though, same principles apply as your runner mould.
Truly epic, good to see someone having a go for nothing more than the sake of having a go. Oh and for some better low down power Have you ever looked at the pugeot 306 s16 inlet setup?
Matt - I forgot for a second what you did but promptly remembered! I still envy that job of yours!! You are correct - Its all pretty the same in terms of layout and so on just that sand is a lot cheaper than a Kg of your best Swedish steel! @ Hasenka, Yes, semi familiar with the Pug intake, from memory it is variable plenum volume rather than runner split runner/de-actavation thus altering reversion pressure wave path lengths as opposed to runner air speed. One based on pressurization effects, the other - mine, based on runner runner cross-section change and the air speed within. The split runner has the added benefit of inducing more incylinder swirl for better air/fuel homogenization at low engine speeds. When I get a Mk2 again for my cylinderhead testing Ill try a few other things. But, until then the 5 series is my bus of choice for the mean time and my right hand man Ed is in charge of the rollers. Ever since meeting Horacio he had an effect on me thats hard to describe. He makes parts that function and that are also made with aesthetics in mind so hopefully when this is done it will have those two important features. Im not for one second saying that looks will come before function, but I am saying I want it to look like something that came from his place, or Ferrari, and not made in a shed in Ireland for 50euro if you know what I mean I spent a while in China on another job a while back and sat in on some of the product design meetings. I learnt that there are a few very simple rules to follow to make something easy on the eye. Its not top of the list obviously, but important to me. Late update tonight - mad late infact - if I let the pictures build it becomes hellish in terms of uploading and describing each one, or should I say trying to remember what you wanted to say about each particular shot So, the mould boxes, got them together more or less. The curved sections where the parting line lies got some birch veneer. Two layers make up the curved portion. The sides are grooved before fitting so that the veneer can be slid in under to hold it. It all gets glued. To add rigidity it will get two layers of twill weave glass on the rears prior to use. In, The veneer has paper on the rear to keep it together. Irrelevant in this case but anyways...its all I had The interior, Two strips screwed in temporary to keep veneer flat against grooved pieces above, plastic to stop strips sticking... Both boxes are done, Next, forming the runner cross-sections within the above boxes, The sweep offset of the runner is draw freehand and cut out from a piece of veneer to act as a template to draw runner curve line, It meets the fillet piece installed into the cutout in the mahogany you saw earlier, Line drawn, work moved into house as the glue dries faster and you can keep an eye on the tv... A profile of half the runner is taken from some kingspan insulation. Its about 1mm smaller to allow for filler, Chop chop.... These then get glued(pva) to the line all the way round to form approx runner half profile, Its like something you would see in H.R. Gigers toolbox lol Distances checked, And checked on insert - bang on to give 4.5mm wall, Same is done on the inside of the top box, They are a little rough, but that doesnt matter - they will get filled between with an epoxy/silica mix and then skimmed with body filler, How we are looking now, Thats the worst of this mould set done now. Tomorrow eve these will be dry enough to epoxy fill, and fill in the last of the pattern pieces. Then its only a matter of filling the curves to smooth with a profile spatula and painting the lot ready for the sand. Time for bed! Brian,
Only got 1.5hrs at it this eve but anyways... Got the epoxy smoothed onto the foam runners ready for filler, Mixing, Thickened with filler powder, Made as thick as grease, holds in place even overhead, Shots of it on the runners at the end of this post as you dont want the phone covered in epoxy Next, the end sections/patterns for the runners + core prints, Two pieces of mahogany held together with end plates and one screw in the centre, To make this, In progress, Shaky shot of radius where runner meets CF tubes, I use a mill roundover bit to check shape, Finished and off - screws removed to reveal both halves, One side is cut flat on both where they meet in center, Like so, Pieces cut free and glued in pairs, Small box(top right) assembled, Pieces get glued in like so once they are checked, Other set get bonded here - also notice runners filled with epoxy mix, Same for this runner pattern, The 'goop' takes 12hrs to set - it dries like granite so a good base for filler. A strong shell is needed on the foam sections for resisting sand packing forces. Brian, @GVK, yep
brian i love this work you are doing and am very envious of your skills, Takes me back to my school days making forms and then forging aluminium and using the lathe to shape what was needed ( not that you can do this in school nowadays!!). Not that it is anywhere near your skills either
I know - its terrible, we had a mill and lathes back in school around about 1998 and nobody was allowed near them really - cant imagine what its like now Either way, glad you are enjoying it! @ Neik, thanks - to be honest I cannot wait either hence the ever increasing pace to get it all done lol Its all pretty simple though as you can see when its broken down into pieces. Got the runners smoothed, or at least now sitting in guide coat waiting for the final fill and few small other bits, A piece of carbon was cut to the half runner cross-section, The piece of veneer which I used to draw curve has been cut back a bit and is used to guide the carbon scraper - here is the first pull of isopon filler, Second, Sanded, Primer to make it all a bit easier see, Blue guide coat and any high/low spots filled/sanded/checked with the carbon form scraper against the veneer guide, Followed by approx 3 more blue coats needed to fully flatten, Other pattern box got the same treatment, Primer, Blue, and more blue! Let sit for a while - tomorrow eve I have to run in a few fillets at some corners, and also add a few other small bits to them. It didn't go too bad. I normally put on far to much filler and there nothing more depressing than sanding off loads of filler in tight spots but the scraper kept things under control! Slowly slowly getting there.... Brian,
Its ''Home Value Hardware Blue'' lol Twas that or pink! Ill have to pull out all the stops and get 'real' paint when we get to that stage! Brian,
Im finally near the end of these patterns and hope to be pouring mid week Got nearly all the other important bits added. All that has to go on now are the tabs for holding while machining + 2 other things. The runner/riser/and sprue details are also on there. To give you a better picture of what they are to look like I did a REALLY rough drawing showing the different parts, Here is how they are laid out within the mould, The metal gets poured down the sprue, hits the filter on the way down then enters the small basin at the base of sprue. From here it flows along the runner and starts filling the portion of the riser below the parting line. It then runs out into the runoff section of runner - this is to trap any loose bits of sand and stuff. The whole system then starts to fill up to the level of the top of the runner. The gate exits the side of the runner in the middle, at parting line. Because the gate travels up hill for a bit to meet with flange the runner system always stays filled. Dross either floats, or sinks so a gate exiting the center is a good idea. From there the metal flows into the flange and around, and fills the cavity. Gate cross-section is critical. If its too big the metal will flow into the part too quick and the filling sprue will drain down as you pour - sucking down air with it. If its too small, not enough metal will flow and the part will freeze before filling fully. When the pour is complete the bottle riser nearest to the flange is also full of metal. The main purpose of this is to aid directional solidification. The part will freeze first at the double barrel end, the solidification travels down along the runners into flange and then into the bottle riser which is the hottest, and which also is the last(hottest) metal in. You have to do it this way otherwise if it started to freeze at the flange end first there is a high risk of the metal contracting too much and tearing where the runner is the thinnest. On a ''Production type'' setup there would be a small bit more science applied, and a few trials done first - but this should be fine as I said at the start this is not a super serious project, nor part. Here is a shot of the runner, bottle riser, and gate, the drawings are terrible and done on my lap so... Here are the parts for real. Remember theres a parting line in here too, so some parts are above and below that line as in the 1st drawing above^ Gate into flange, Its left a tiny bit lower that the flange thickness so when poured you have a straight line to cut it off along, Here is the floor to attach to that same insert piece, The exit from bottle riser meets with the gate when the floor is screwed to box. Remember this floor has to release from the sand too, so no locking shapes here either... This is its position when the box is getting filled with sand, Of course before it is filled, the sprue pattern has to be stuck down through the top piece in order to form the void needed for pouring - the top of this sprue pattern lies below the filter section the the box above it....Im just noticing its not shoved fully home in this shot, The lower box, spot the added piece on the runner for a communal tube I want to run between them all for isv/5th injector/whatever, also spot the lower pieces of the runner assemblies, It also needs a fillet here as this is the location where the runner meets the back of the flange, More paint... Tiny bit of work left now with them + a day drying and we shall be ready for sand, Brian,
