How about making our diesels out of Resin Molds instead of injection molds?
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quote:Originally posted by R.R.:
How about making our diesels out of Resin Molds instead of injection molds?
Resin molds are only good for so many castings, they're made of flexible material and may not produce a good casting each time. Plus, it's a slow process, the resin has to set up and cure before the mold is peeled off.
Rusty
Resin is not the greatest stuff to use on something that may get knocked around and require a fair amount of handling. ABS has some shock absorbency built in. You can run an injection molding machine at a pretty decent clip, resin casting requires a fair amount of "cure" time. Not really suitable for large production runs. ABS can also be fused by heat, chemical, and possibly ultrasound. Resin usually require epoxy or CA glues to assemble parts.
quote:Originally posted by Rusty Traque:quote:Originally posted by R.R.:
How about making our diesels out of Resin Molds instead of injection molds?
Resin molds are only good for so many castings, they're made of flexible material and may not produce a good casting each time. Plus, it's a slow process, the resin has to set up and cure before the mold is peeled off.
Rusty
Use to be a company years ago called Design Preservation Models.They couldn't meet production schedules and fell way behind.
Rusty's post is the reason Walthers owns DPM now.
David
The advantage to resin casting is that it has a low up front cost. The molds don't cost much and you really don't need any specialized equipment to make one. The disadvantage is that it is a slow process and is fairly time intensive.
The advantage to injection molding is that parts can be made in seconds rather than minutes to hours. Molds are metal and can be used to make large runs over and over again. A disadvantage is that these molds are expensive to make. The hotter the material being injected, the more it shrinks so a mold actually has to be over-sized. You also need a special injection molding machine which too can get very very expensive. The actual cost per part is very low though.
Resin casting is fine for the hobbyist or a person who wants to make limited numbers of things. For larger scale production each part will cost more due to resin costing more than the plastics used in injection molding. Parts will take much longer to make which means fewer can be made per time. Each mold may make dozens of parts but will ultimately need to be replaced much sooner as opposed to an aluminum mold that may be used thousands of times. Your costs are up front with injection molding with savings on the back end whereas with resin casting your savings are up front with greater cost per part. Time also costs money.
Can you resin cast locomotive shells? Sure you can. Whether or not it is feasible is dependent on what your production number intentions are.
The advantage to injection molding is that parts can be made in seconds rather than minutes to hours. Molds are metal and can be used to make large runs over and over again. A disadvantage is that these molds are expensive to make. The hotter the material being injected, the more it shrinks so a mold actually has to be over-sized. You also need a special injection molding machine which too can get very very expensive. The actual cost per part is very low though.
Resin casting is fine for the hobbyist or a person who wants to make limited numbers of things. For larger scale production each part will cost more due to resin costing more than the plastics used in injection molding. Parts will take much longer to make which means fewer can be made per time. Each mold may make dozens of parts but will ultimately need to be replaced much sooner as opposed to an aluminum mold that may be used thousands of times. Your costs are up front with injection molding with savings on the back end whereas with resin casting your savings are up front with greater cost per part. Time also costs money.
Can you resin cast locomotive shells? Sure you can. Whether or not it is feasible is dependent on what your production number intentions are.
quote:Originally posted by fredswain:
Can you resin cast locomotive shells? Sure you can. Whether or not it is feasible is dependent on what your production number intentions are.
In S Scale, Smoky Mountain Model Works made GE 70 tonners, 44 tonners and FM H10-44's. They were relatively small runs, well designed kits and the ones I've seen built up are pretty nice.
The H10 kits's were moderately expensive: $325.00 for scale and $345.00 HiRail, which reflects the amount of design, materials, labor and small production run involved.
Rusty
