Building Prototypes Part 12 of 18 Plastics Forming and Casting

Building prototypes for R&D and low volume production

[@ar5000]

I'm pretty good at prototyping. However, I'll watch an entire 10-30 minute video from Dan, and still get at least 1 REALLY good nugget of info that makes me rethink how I'm doing something. This series is GOLD and this is time well-spent for anything making stuff in shop.

[@jeffflanagan2814]

I love your smirk when you're talking about something really cool! Great videos! Keep them coming

[@deepwinter77]

I'd love to see some more video's Dan, there fascinating.

[@ptdecker]

How anyone could do a thumbs-down on this guy is beyond me

[@willrod1025]

I hope you make more videos

[@emo65170]

Excellently presented. Thanks!

[@Rollmops94]

I wish you explained the aluminium-alloy casting a little more in depth. Obviously you can't suck the molten metal in using the vacuum. At least it seems dangerous to me. So would you pour it in and then degas the package afterwards? I really wonder if there are any benefits to the vacuum suction method anyways. I don't really want to drill a hole into my chamber to test it though.

[@dgelbart]

The vacuum suction method eliminates the large foaming happening in vacuum degassing, but is not essential. Molten metals, like aluminum, have very low viscosity so they can be vacuum degassed quickly without the suction feed method.

[@dgelbart]

When you cast low-melting point metals into silicone molds you just pour the metal in, no vacuum used. Molten metals have very low viscosity and high density, so all the air bubbles are pushed to the surface instantly.

[@uriuriuri]

4:55 when Dan fesses up to bootlegging Miles Davis LPs

[@duroxkilo]

good one mr Uri... on a sidenote, the dynamic range is closer to 70dB than 100dB when it comes to vinyl, good quality direct-cut vinyl that is.. unless mr Dan was talking about a 'master' which may have 100dB dynamic range, i have no idea

[@PplsChampion]

the marlon brando of prototyping

[@marklagana2769]

are you saying you cast an LP using a silicone mold and it worked? I'm not saying it's impossible but i feel you would need such low viscocity silicone to flow into the grooves that the silicone would not be able to withstand the heat of thermoplastics. Thermoset resins maybe but the low viscocity silicone is so weak it wouldn't be very repeatable and something like polyurethane resin would probably shrink to much to be reliable. (i love your videos by the way you're my hero) i was lucky enough to work with some vintage vinyl presses, the EMI 1400 incase anyone is interested, EMI headquarters would use a special lathe to cut the grooves into either aluminum covered in acetate laquer, or copper. I believe the lathe cuts with sapphire. From this, industrial magic, not really sure but after some process negatives were created in Nickel using electroplating. These thin Nickel negatives were sent to us, protected in peelable plastic then a spray with compressed air (dust) and put onto the top and bottom stampers which were giant harderned steel flat surfaces (record shaped). The nickel would get bolted in the center and tightened around the circumference with a large threaded ring. PVC pellets would get vacuum sucked into a auger and extruded into a handful-sized plastic puck. The machine then pushed the oven dried paper labels into the top and bottom of the puck whilst also picking it up and placing it in the center between the two stampers. The stampers had low pressure steam running through internal pipes very hot, they would close together (i think also using steam power), and pause to allow the PVC to re-melt at this hotter temp, i think then the stampers closed together slowly to the final position and paused to allow the pvc to flow into the grooves. The steam in the stampers was replaced with cold water, they would open and the solidified record would be stuck to the bottom stamper, where a hot knife would slide in to the edge and the stamper would rotate, cutting the trim. It would pop up and a linear axis would transport it to a rotational axis that gave it a guided drop into the inner sleeve then another guided fall onto the stack. All the axes were pneumatics with compressed air, the 'end stop' was to smash into the end of the axis and remain smashed And before anyone corrects me, I know the nickel negatives were actually called stampers and the giant heavy flat surfaces they bolted to were called moulds but i hate that terminology

[@dgelbart]

The reason you can reproduce nanometer size details in silicone rubber of fairly high viscosity is the wetting and capillary action. Silicones in general have very low surface tension, so they "pull themselves" into the grooves. When you press records you don't have this mechanism to help you, as the polymer does not wet the nickel, and you have to force it in. Just think how this mechanism lifts water to the top of the tallest trees. Without surface energy release (wetting in a capillary) you would need an enormous pressure to pump the water to the top of the tree. Unfortunately, the subject of surface energy, critical to so many processes, is not taught in engineering school. You are not the only one who was surprised by this process.

[@marklagana2769]

@@dgelbart thanks for the reply, fascinating.

[@Tadesan]

A ten thousand dollar oven and a sixty dollar vacuum cleaner!

[@stephendumaine1575]

i though he made the oven! Dan, did you make the oven?

[@Tadesan]

He probably did. Ok a twenty thousand dollar oven.