{"id":126547,"date":"2022-01-23T18:02:42","date_gmt":"2022-01-23T17:02:42","guid":{"rendered":"https:\/\/atomicalex.com\/?p=126547"},"modified":"2022-01-23T18:02:42","modified_gmt":"2022-01-23T17:02:42","slug":"casting-urethane","status":"publish","type":"post","link":"https:\/\/atomicalex.com\/?p=126547","title":{"rendered":"Casting urethane"},"content":{"rendered":"\n

The 3D printing thing escalated quickly.<\/p>\n\n\n\n

I figured out how to make robot wheels.<\/p>\n\n\n\n

  1. Print a mould. I used PETG as it polishes up nice and holds the mould release agent well. This is for a custom robot wheel. The piece in the middle with come with the urethane when I break it out. The center fits on a 1\/2″ hex shaft and the little notches are to hold the urethane better. I used Smooth-On Universal Mould Release for the agent.<\/li><\/ol>\n\n\n\n
    \"\"<\/figure>\n\n\n\n

    2. After spraying the mould with mould release, I made up the urethane rubber. I used PMC-744, a 44A Shore compound. It’s quite floppy, which is perfect because this wheel needs to be ultra compliant.<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    3. The urethane is a 2:1 mix, and I made 75gr which turned out to be twice what I needed. I need to get better at estimating how much resin I need by doing volume calcs or just filling with water and weighing.<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    4. Next step is the actual pour. I have the mould sitting on a silicone release pad. Parchment paper also works.<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    5. Next is the poured mould. I have to strike it off to make the sides level and get the rubber evenly distributed. I could pressure cast it, but I do not have a pressure pot. I sometimes vaccum the castings to get the air out, but not for this test wheel. <\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    6. Last step is to cover it up. Urethanes STINK, so controlling the environment is really useful. Thankfully I have some leftover Gladware to do the job. A few of the Gladware containers are really handy if you craft a lot.<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    I’ll post up the wheel when I pull it tomorrow!<\/p>\n","protected":false},"excerpt":{"rendered":"

    The 3D printing thing escalated quickly. I figured out how to make robot wheels. Print a mould. I used PETG as it polishes up nice and holds the mould release agent well. This is for a custom robot wheel. The piece in the middle with come with the urethane when I break it out. The […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-126547","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/posts\/126547","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/atomicalex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=126547"}],"version-history":[{"count":3,"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/posts\/126547\/revisions"}],"predecessor-version":[{"id":126556,"href":"https:\/\/atomicalex.com\/index.php?rest_route=\/wp\/v2\/posts\/126547\/revisions\/126556"}],"wp:attachment":[{"href":"https:\/\/atomicalex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=126547"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/atomicalex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=126547"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/atomicalex.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=126547"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}