Resin Copies, Mold and Cast medium size parts

this is a part that i just got from  a customer and they asked if we could   make some resin duplicate parts it's a standard  injection molded uh part made by a swiss company   we're gonna make a two-part silicone mold so we  can make resin parts this is a great use case   for making resin parts if you're let's say  prototyping even a 3d printed master part the   parts that you get are a lot more durable than a  3d printed part and you can make them virtually   any color that you want my name is Eric Strebel  i'm an industrial designer welcome to my channel   about product design and making there's nothing  particularly special about this enclosure other   than i would say it's a medium size enclosure so a  little bit bigger than the table top stuff that i   normally do i'm going to clean it really good with  some denatured alcohol as a bunch of crud on it   and i'm going to build a mold box i'm going to  build this mold box out of some half inch mdf   laminate material that i have meaning it's  laminated on both sides it has a pretty smooth   surface and so it'll lend itself really well to  building a mold box this mold box is 18 by 34   by roughly 10 or 11 centimeters you want your  mold box to be nice and square i'm gonna screw   this mold box together because i don't have  an existing one that is the correct size   i pre-drill and countersink all the holes because  it is particle board and it's basically crappy   low-grade material so i have to be particularly  careful so that i don't split the material   it's easily it splits and uh could leak silicone  which i don't want so screw everything together   with i don't know inch and 7 8 drywall screws  doesn't take too long to make a mold box like this   but i prefer this over using some sort  of a throwaway material like a foam core i mark the sides so i know how it goes together  and then i use the laser and this is the key   to making a ceiling mold box i cut out these  keys that go around the inside of the mold   box and just cardboard you'll see a lot of guys  that use these round dots that they use as keys   to line up their mold boxes and the two halves of  the molds i don't do that at all and i use these   keys that i laser cut 360 degrees and in this  case the two top pieces of cardboard are thicker   than the two bottom layers and that's going to  give me a locking mechanism so here's a section   of the part and a section of the mold and there  you can see my four layers of cardboard and my   mold so this basically gives me a mold that locks  onto the bottom half of the mold on the outside   giving me my two pieces and a self-locking mold  so i've started to make molds like this as they   line up perfect every time and i don't  need to do all the thing with the keys   there are some openings on this part that  normally would be made you know when it   was injection molded with some slides and  i'm going to seal those up with some tape   some packing tape and basically what i'm  doing here is i'm preventing the silicone   from going into the other side of the  mold i'm going to use some white glue pva   to glue my object down to the bottom of the mold  box and this creates a seal so that no silicone   gets underneath the part when i pour the silicone  in there and that's important that way there's   nothing to clean up and the pva white glue just  peels right off the mold box because i want a   parting line that's super clean down at that  edge of the mold box of the part excuse me and   i'm putting in these pens here these are merely  locating pins because this is a square mold so   you could easily reverse the top and the bottom  when you put it together and so that's locating   pins just to make sure i put the mold together  correctly every time let's mix up some silicone   this is a shore 30a silicone so this is  a little softer than i would normally use   and the only reason i'm using this soft silicone  is that this is what i could get a hold of   in short order normally i use a 40 a durometer  silicone but i didn't have any and i couldn't   get any in the short amount of time for this  kind of budget project so i had to use this 30   shore silicone and into the vacuum tank it  goes this is super important you want to degas   your silicone to take all the air out of the  silicone before you put it into your mold   so that you don't get any bubbles in the silicone  and that you don't have any defects in your part   you'll notice i pour the silicone in one  corner and i want to let the silicone rise   naturally around the part 360  degrees once it it's risen to the top   then i can pour some more in and be a little bit  more uh aggressive you'll see the stuff that i   scrape out of the container this is where it  has all the air bubbles it's just from mixing   and handling the the silicone is where  you get air bubbles we'll take it apart   the goal here is to keep the part inside the  silicone we do not want to remove the part i mean   sometimes that happens to me and i have to take  it out but our goal here really is just to drop   this part and lower it in the mold box so that  we can have some walls that come up above it   to make the second half now i'm removing  that cardboard those are disposable parts   my locking elements and i'm going to add a little  bit of release agent this is vaseline that's   thinned out with naphtha and this prevents the  new silicone that we're going to pour into this   from sticking to the existing silicone and  this is super important now we're going to   reassemble the mold box in the same way around the  object so that we have a little bit higher walls   i'm attaching our vent holes and these are done  uh with either they're cast from plastic straws   some urethane i have kicker on a  paintbrush and some super glue on   the other side and i just attach it to the  part and the last piece was the pour sprue   we're gonna mix some silicone to pour  the other half of the mold again mix it   thoroughly and then mix it some more that's my  rule into the vacuum tank it goes to be degassed   takes i don't know 10 10 ish minutes 10 15 minutes  something like that for silicone it's pretty thick   weird material and i pour it in one spot the same  thing i let the mold fill up i did not have enough   room in this container and i needed to do a  second pour just fyi this mold box is about   four liters so each pour is roughly 2.2 liters  of material once the silicone is cured overnight   it's time to disassemble i remove the pour sprue i  remove all the little vent holes i take out the um   mold box around it and i peel the two halves  of the mold apart and i remove my master part   let's move on to adding a little bit of mold  release to the molds before i assemble it now   normally i don't use mold release but in this  case it's a textured part and it's pretty big   and i want to make it a little bit easier  for myself i reassemble the mold with those   locking halves so i don't need any rubber bands  i don't need any weights or anything like that   i mix up the appropriate amount of resin  i add my dye and my color again that's the   beauty of this system is you can  dye your parts any color you want   you need to degas this resin before  we put it into the actual mold this takes a minute and a half something like that  get all the air bubbles out remove it from your   pressure tank and we're going to pour it into the  mold now you'll notice i pour the resin against   the side of the funnel and this is important to  reduce the amount of turbulence you don't want   to just dump it down the middle of that funnel  you're going to get air bubbles in your part and also i find that pouring your resin a little  bit thicker may almost letting it set up will also   reduce the amount of bubbles so there you can see  the cast part and the original there's very very   little flash on the part along that seam line  on the top i take a pair of flush cutters and   i can trim off the vent holes and there's very  very little post-processing that has to happen   i need to make 10 of these units for my  customer and so i want to do as little possible   after i mold them than i need to there's  a little bit of setup work to do of course   when you make all these molds and everything  but you want to just pop them out of the molds   and then that's done here's some of the parts   and you can see probably the hardest part of this  project in many ways was just getting the color   right and took a few pours  to figure out the color value make sure you give the video  a thumbs up hope you liked it   rock on don't forget to follow me on social media   and you can check out some of the other videos  that i have that you may like don't forget to   hit the notification bell as well so you can  be notified about any future videos that i have

Channel: Eric Strebel

Views: 57,689

Keywords: Industrial Design, Product design, Consumer product development, Eric Strebel, consumer products, design and making, product development, model making, prototyping, silicone molds, resin parts, advanced mold making, polyurethane resin casting

Id: 3obngISQ_yk

Length: 11min 28sec (688 seconds)

Published: Thu Sep 09 2021