Understanding Injection Molding Quotesmap :: {skin:’green’, animate:true, width:’200′, volume:0.6, autoplay:false, loop:false, showVolumeLevel:true, showTime:true, showRew:true, downloadable:false, downloadablesecurity:false, id3: false}

[Transcript]

Audio File: 2014 Mar 14 – Understanding Injection Molding Quotes.mp3

Audio Length: 20:19 minutes

Hi, my name is Montie Roland. And I’m with Montie Design in Morrisville, North Carolina. We’re a full-service product development firm providing engineering services, industrial design services, and prototyping. So, we can help you design it; help you think through the concept; and then build you a prototype and provide the assistance you need to make the connections you need to manufacture your product, domestically or abroad.

This morning I’d like to talk about understanding an injection mold quote. And really, this . . . when you look at it and break it down, this also applies to most other manufacturing processes, the way that it’s structured.

So, if we’re going to create an injection-molded part, we need two things upfront. One thing is we need a completed design – and that needs to be in 3-D CAD – and then we also need to know what the material . . . materials used in the product are, which is really part of the design, but let’s break it out for the purposes of this discussion. That completed design is going to include 3-D geometry that you’re going to release to the molder as a .STEP file or a .IGES file. And it’s also going to include a drawing. That drawing will include any critical dimensions, any critical to function, any inspection dimensions. Also, secondary operations – if you’ve got a drill a hole in the part; or if you’ve got to put a threaded insert in.

So the drawing is no longer what we call “fully descriptive”. Fifteen years ago, drawings had to describe everything that you wanted to control about that part. If you wanted to control the size of a radius, you needed to create a section view and show that radius. Which, you can imagine, for an injection molded part, was an onerous task, because there’s a lot of details in a part like that. So, now what’s happened is we have parts that are defined in 3-D on the CAD – it’s in SolidWorks or ProEngineer; Catia; Unigraphics; what have you. And so those parts give a tremendous amount of information to the mold maker. So, no longer is the mold maker having to interpret a drawing. A lot of their tool pass and a lot of their mold design comes from your model directly, which makes for quicker tool builds because they don’t have to model the part. And also more accurate because they’re not interpreting from a 2-D drawing.

So, .STEP file; drawing, probably in a PDF format; and then your material choice. With plastics there’s a whole bewildering array of materials. A lot of times, though, parts end up being made out of common materials, such as ABS or nylon. These materials can also be filled. You can use a mineral fill, like a talc; you can have a foaming agent if you want to have a part that is a foam part. You can also fill it with fibers – long or short. And those fibers can give materials like nylon really, really great stiffness. And so you select that material. If you have questions about that, you know, the best thing to do is ask someone who has a good background in plastics injection molding. Also, you can work with your material provider. Depending on how exotic the material is, you may have to make a choice between . . . you may have to choose a provider like RTP that provides smaller quantities if you want something that’s more of a custom material. You remember, a lot of plastics are sold by the train car load, so if you make a few thousand parts, obviously, you use a lot less than a train car load. So, a custom material means you go to someone who deals in custom materials like RTP – which drives the cost per pound up dramatically. But if you have an application where you need some e