PBV Part 4: What information do I need to have to get a quote from China – Part 2 – Prototype

Manufacturing in China – Pulling Back the Veil, Part 4

This is Part 4 of a 10 part series called “Pulling Back the Veil” that aims to answer the basic question “how do I manufacture my product in China”? These articles are primarily step-by-step instructions and directly applicable information about manufacturing in China. To see the other “Pulling Back the Veil” Articles, click the “Pulling Back the Veil Link” under the categories section to the right.

As discussed in the last post, in order to get a quote from China you will need: Engineering Drawings, a Bill of Materials, Specifications for those components, and a prototype. Not all of these are necessary depending on your product, but the more you can provide, the faster and more accurate the quote and final product you will receive will be. In general, one does not necessarily come before the other as they are all related and get modified throughout the development process. In this article we’ll talk about some ways to make a prototype and some things you should know about prototyping.
There are different prototyping processes for different materials, so we’ll break them up accordingly.

Plastics

There are a number of new and old technologies that can give you a decent quality prototype for plastics. Some of the most common include SLA (stereolithography), RTV (Room Temperature Vulcanization), CNC (Computer Numerical Control) Machining, and 3D printing. There are a slew of ways to get it done and which process you want to use will depend on your structural, surface finish, price, dimensional tolerance and other requirements. I’ll write another blog discussing the pros and cons of each in more detail down the road.

For plastics more than other materials though, it is difficult to make the prototype similar to the final product. The processes above are each much different than what happens to plastic material when it is melted and injected or otherwise molded. The basic molecular makeup is different leading to different material properties such as flexibility, hardness, color….even when using the same raw materials. You simply can not get a plastic prototype to be exactly like a tooled product, so before banking on it to help you make your decisions, make sure you know what the differences will be given your prototyping technique.

Metals

CNC Machine

Metals are a bit easier to prototype than plastics due to their ductility and hardness. CNC machining is the most common process for making prototypes. It can make very finely detailed parts…it’s just usually too expensive for mass production. Another advantage is that tooling for metals is generally much cheaper. If you plan on using some fixtures or tooling for mass production, you might be able to go ahead and purchase them before prototyping as they may only run a few hundred dollars (of course some tooling is MUCH more expensive than that, but it’s worth looking into).  If you can use the mass production tooling  you can get to a prototype that will be very close to your final production. Although it’s generally easier to match a metal prototype, you must be careful about the raw materials and the heat treatment. Using different raw materials for the prototype, or not heat treating them the same way you plan to in mass production can lead to much different results.

Fabrics

Fabric Swatches

Fabric products are probably the easiest to prototype and to match with mass production. If you’ve seen a good seamstress at work, you can understand just what magic they can work with some scissors, a template, and a sewing machine on a raw piece of fabric. There are some processes that can improve the overall quality that need fixtures (like die-cutting the material which can cut complicated shapes very precisely) which usually wait for mass production, but as long as you understand this, you can get a pretty good idea of what your final product will look like with a well done prototype.

The prototyping stage can sometimes be accomplished more effectively domestically than in China. It is generally about 2-5 times more expensive locally, but you also save a lot in shipping costs. Most importantly, almost no prototype ever comes out right the first time. That is just a part of development. Doing it overseas makes it much more difficult to see the prototype as it’s coming together and make changes on the fly. The extra shipping time can also drag out your timeline (though if you do it domestically, be sure the person you are working with has time for your product. Even though they are just down the road, some prototyping companies won’t have time in their schedule for you for a few months some times). The big advantage of doing it in China is that if the prototype comes from the factory you will be working with, then they will already understand the abilities of their machines and will make a more manufacturable prototype. Even very high level engineers in the US often are not familiar with the details of available/common equipment and processes in China and don’t always take that into account in their designs.

Remember the purpose of the prototype

The purpose of the prototype is not to make a perfect prototype. What are you going to do with that except admire it? The purpose is as a tool to help you make decisions about your product. So, before you rush into it, make a list of questions that you expect the prototype to answer for you. Marketing questions? User interface? Functionality? Materials? Every product will have different areas of concern. Focus on those when you are making your prototype instead of just trying to make it perfect.
We had a client who spent 12 years making a prototype! I’m still not sure if he has completed it. Unless you are doing this as a hobby, remember the goal is to take your product to market. Be focused on that goal through all stages of the process, but particularly when working on the prototype. This is a common black hole for inventors and small businesses from which many never escape.