Take a look and start casting.<\/p>\n
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What is Urethane Casting?<\/strong><\/h2>\nUrethane is a type of resin that\u2019s used to make a range of plastic items. It\u2019s end-use is highly versatile; you can create both flexible items that are almost rubbery in texture, and very rigid plastics.<\/p>\n
Urethane casting\u2019s in the manufacture of short-run, low-volume products such as movie props or bespoke models. It involves pouring the urethane into a mold and letting it cure \u2013 but we\u2019ll talk more about the process later.<\/p>\n
Urethane casting is a brilliant low-cost, high-quality way to create parts and whole models. It works well for detailed designs too, creating a high standard finish quickly and without the high price tag of other methods.<\/p>\n
Urethane Casting Process <\/strong><\/h2>\nCasting urethane can be tricky, so we recommend ordering a tester sample before a big order. You\u2019ll be able to get to grips with the process, work out whether you like the resin, and avoid losing too much in failed attempts.<\/p>\n
Most of us mess up a few times when trying a new resin, so don\u2019t worry if it doesn\u2019t go to plan!<\/p>\n
The process starts with a silicone mold. In order to create this mold a master model of the parts will be manufactured by 3D printing<\/a> or CNC Machining<\/a>, then by pouring the silicone into a tool imprints of the parts will be shaped.<\/p>\nYou then have to mix your urethane, which comes as two separate liquids. You should mix the parts in a 1:1 ratio or as directed on the brand instruction. As soon as you mix the two, a chemical reaction starts that turns them from liquid to solid \u2013 this is curing.<\/p>\n
You may also hear curing being referred to as room temperature vulcanization. It may sound more advanced, but it really is the same thing.<\/p>\n
If you\u2019re adding a tint to your resin, remember to do it before combining the two liquids. It can take a while to mix the tint so this will give you more time. If you add the tint to the combined resins, the urethane may start to set before you\u2019ve thoroughly mixed it.<\/p>\n
Once you\u2019ve mixed the tint, you can combine parts A and B of your urethane. Stir this for between 10-20 seconds. You can then carefully pour it into your mold.<\/p>\n
Leave your urethane for around 1 hour to cure \u2013 although you can follow the brand\u2019s guidance for timing. Remember to always read their safety information, too, and they can tell you more about pot life and pouring techniques.<\/p>\n
Once the resin is properly cured, remove it from the silicone mold \u2013 easy! They can repeat the operation up to 20 times.<\/p>\n
Things to Remember When Using Urethane <\/strong><\/h2>\nUrethane can be affected by many factors. Remember these so that they don\u2019t affect your final parts:<\/p>\n
\n- Urethane hates moisture<\/strong> \u2013 As soon as urethane comes into contact with moisture, it reacts. Even the water in the air can ruin your urethane, which would be a pain after you\u2019ve just bought two large jugs. So, always remember to put the caps back on your urethane as soon as you\u2019ve poured it. This will help it to last longer and work better.<\/li>\n
- Urethane is exothermic <\/strong>\u2013 An exothermic reaction is when the heat is created, and this happens to urethane whilst it cures. Because of this, areas with a higher volume of concentrated urethane will cure faster than thinner areas. Just because one area is ready doesn\u2019t mean the whole part is, so be sure to leave it for long enough for everything to dry. The exothermic reaction will also evaporate heat from your mold which can cause damage.<\/li>\n
- It will shrink <\/strong>\u2013 As your resin turns from liquid to solid, it\u2019ll shrink. With urethane casting, you expect shrinkage of around 0.15%, which you\u2019ll have to bear in mind when creating your mold.<\/li>\n
- Your tint will be affected by the base color<\/strong> \u2013 The base color of urethane is usually white. It can also be black, translucent, or colored. Remember that whatever base color you pick will affect your final color when you use a tint. So if you choose a white base and red tint, for example, it\u2019ll more likely come out pink.<\/li>\n
- You can paint urethane <\/strong>\u2013 Don\u2019t worry too much about tint if you\u2019re finding it too hard to color match. You can also paint your urethane parts. We still advising tinting your parts though to a similar color; this will help if your paint chips and reveals the urethane beneath.<\/li>\n<\/ul>\n
Each urethane brand will be slightly different, so always read the advice and guidance from your brand before using it. This will help you get the best finish and make sure your urethane lasts for its full pot life.<\/p>\n
What is Plastic Injection Moulding and How Does it Compare?<\/strong><\/h2>\nChoosing the right process for your project is vital to its success, even if they seem similar.<\/p>\n
If you\u2019ve been doing some research, you might have noticed that plastic injection molding<\/a> and urethane casting look quite alike. But, this is only on the surface.<\/p>\nTo start with the process itself, it uses very different techniques. Urethane casting involves the use of hand-operated vacuum machines to draw liquid material into a mold.<\/p>\n
There\u2019s also a difference in the molds used. Whilst urethane uses silicone, injection molding usually uses metal. The materials used for the cast are also very different. Urethane is a polymer that mimics the production-grade plastics (like PVC and ABS) used in plastic injection molding.<\/p>\n
Finally, there\u2019s quantity. Plastic injection molds usually have a ton of cavities in one mold so they can create more products in one cycle. Urethane molds typically only have a few \u2013 or one \u2013 cavity and make fewer pieces.<\/p>\n
Urethane Casting Vs. Plastic Injection Moulding Differences<\/strong><\/h2>\nNow you know more about the processes, let\u2019s take a look at some of the other differences you should consider:<\/p>\n
\n- Upfront costs<\/strong> \u2013 Injection mold can be far more expensive than urethane casts as they\u2019re made from metal. This makes this system more of an investment and better for long-term, mass-production. The molds for urethane casts can be made for me much less, helping you reduce upfront costs. This makes it better for one-off designs or low-volume batches.<\/li>\n
- Cost of materials <\/strong>\u2013 Just like the molds, the production-grade plastic that you\u2019ll need for injection molds is much more expensive than urethane. This includes PVC, ABS, acetal, and LPDE. Once again, this makes urethane the better choice for prototypes and low-volume work.<\/li>\n
- Lead times<\/strong> \u2013 The molds for injection molding can take a very long time to make \u2013 sometimes even months! This increases lead times and can prevent quick delivery of products. Usually, the molds are 3D metal printed<\/a> to try and speed up the process. Urethane silicone molds are much quicker to make. Usually, they can be created with a 3D printer or even by hand, reducing lead times and helping you get your product to market quicker.<\/li>\n
- Per-part cost<\/strong> \u2013 Usually the bottom line, the per-part cost will be higher for urethane than injection molding. This is because you can only make a few pieces with each mold. On the other hand, the higher volumes produced by injection molding make them much cheaper. This reduces those previous higher costs, like for materials and tools. In this way, injection molding is usually the most cost-effective molding for long-term production.<\/li>\n<\/ul>\n
Plastic Injection Modelling or Urethane Casting?<\/strong><\/h2>\nSo, which one\u2019s better for you? That comes down to what you need to make \u2013 there isn\u2019t one superior option.<\/p>\n
The cheaper upfront costs and quicker lead times will always make urethane better for porotypes \u2013 unless injection molding is essential. Whereas for product runs of larger numbers, you\u2019ll get a much better ROI with injectable molding and the steel molds used will last far longer than the silicone alternatives.<\/p>\n
Benefits of Urethane<\/strong><\/h2>\nStill not sure if the urethane casting process is the option for you? Let\u2019s run through some of the benefits:<\/p>\n
\n- You can test out your design and ensure there is a market for it before going into mass-production. It\u2019s a working prototype that isn\u2019t too expensive. Once your product switches to higher volumes you can change to a different process.<\/li>\n
- It gives you low-volumes of high-quality, production-grade parts.<\/li>\n
- You can create very detailed models and have more freedom with your designs. This is ideal for bespoke props and models. You can even create internal, sharp corners, which can be trickier with other processes.<\/li>\n
- You can bring your product to the market quicker with short lead times.<\/li>\n
- It can cure to a variety of finishes, from very rigid to incredibly flexible.<\/li>\n
- It\u2019s available in tons of different texture, finishes, and tints can be added to change the color. This means you can tailor your casting to suit your end-use.<\/li>\n
- The shrinkage rate of 0.15% is much less than many other processes.<\/li>\n
- Urethane castings can be FDA approved, which is essential if you\u2019re making items for the food, medical, and pharmaceutical industries.<\/li>\n<\/ul>\n
Drawbacks of Urethane<\/strong><\/h2>\nThere are some drawbacks to urethane casting. Make sure you know what they are before making your decision:<\/p>\n
Casting urethane can be tricky, so we recommend ordering a tester sample before a big order. You\u2019ll be able to get to grips with the process, work out whether you like the resin, and avoid losing too much in failed attempts.<\/p>\n
Most of us mess up a few times when trying a new resin, so don\u2019t worry if it doesn\u2019t go to plan!<\/p>\n
The process starts with a silicone mold. In order to create this mold a master model of the parts will be manufactured by 3D printing<\/a> or CNC Machining<\/a>, then by pouring the silicone into a tool imprints of the parts will be shaped.<\/p>\n You then have to mix your urethane, which comes as two separate liquids. You should mix the parts in a 1:1 ratio or as directed on the brand instruction. As soon as you mix the two, a chemical reaction starts that turns them from liquid to solid \u2013 this is curing.<\/p>\n You may also hear curing being referred to as room temperature vulcanization. It may sound more advanced, but it really is the same thing.<\/p>\n If you\u2019re adding a tint to your resin, remember to do it before combining the two liquids. It can take a while to mix the tint so this will give you more time. If you add the tint to the combined resins, the urethane may start to set before you\u2019ve thoroughly mixed it.<\/p>\n Once you\u2019ve mixed the tint, you can combine parts A and B of your urethane. Stir this for between 10-20 seconds. You can then carefully pour it into your mold.<\/p>\n Leave your urethane for around 1 hour to cure \u2013 although you can follow the brand\u2019s guidance for timing. Remember to always read their safety information, too, and they can tell you more about pot life and pouring techniques.<\/p>\n Once the resin is properly cured, remove it from the silicone mold \u2013 easy! They can repeat the operation up to 20 times.<\/p>\n Urethane can be affected by many factors. Remember these so that they don\u2019t affect your final parts:<\/p>\n Each urethane brand will be slightly different, so always read the advice and guidance from your brand before using it. This will help you get the best finish and make sure your urethane lasts for its full pot life.<\/p>\n Choosing the right process for your project is vital to its success, even if they seem similar.<\/p>\n If you\u2019ve been doing some research, you might have noticed that plastic injection molding<\/a> and urethane casting look quite alike. But, this is only on the surface.<\/p>\n To start with the process itself, it uses very different techniques. Urethane casting involves the use of hand-operated vacuum machines to draw liquid material into a mold.<\/p>\n There\u2019s also a difference in the molds used. Whilst urethane uses silicone, injection molding usually uses metal. The materials used for the cast are also very different. Urethane is a polymer that mimics the production-grade plastics (like PVC and ABS) used in plastic injection molding.<\/p>\n Finally, there\u2019s quantity. Plastic injection molds usually have a ton of cavities in one mold so they can create more products in one cycle. Urethane molds typically only have a few \u2013 or one \u2013 cavity and make fewer pieces.<\/p>\n Now you know more about the processes, let\u2019s take a look at some of the other differences you should consider:<\/p>\n So, which one\u2019s better for you? That comes down to what you need to make \u2013 there isn\u2019t one superior option.<\/p>\n The cheaper upfront costs and quicker lead times will always make urethane better for porotypes \u2013 unless injection molding is essential. Whereas for product runs of larger numbers, you\u2019ll get a much better ROI with injectable molding and the steel molds used will last far longer than the silicone alternatives.<\/p>\n Still not sure if the urethane casting process is the option for you? Let\u2019s run through some of the benefits:<\/p>\n There are some drawbacks to urethane casting. Make sure you know what they are before making your decision:<\/p>\nThings to Remember When Using Urethane <\/strong><\/h2>\n
\n
What is Plastic Injection Moulding and How Does it Compare?<\/strong><\/h2>\n
Urethane Casting Vs. Plastic Injection Moulding Differences<\/strong><\/h2>\n
\n
Plastic Injection Modelling or Urethane Casting?<\/strong><\/h2>\n
Benefits of Urethane<\/strong><\/h2>\n
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Drawbacks of Urethane<\/strong><\/h2>\n