How to Design and Manufacture a Prototype for Manufacturing Purposes

Prototyping is a cost saving process used in the plastic product manufacturing industry. While most clients understand this process in general, there are many points that are taken into account to create a prototype worthy for manufacturing. This article provides the various important points that plastic manufacturers have to consider during prototyping.

As most customers know, prototyping is a process, where a mock-up of the final product is created. Prototyping provides a variety of advantages. These include design flexibility, detecting and fixing defects before manufacturing, and cost-savings. Nonetheless, the process of prototyping is extremely important, and many points need to be considered to create a prototype that is fit for manufacturing. This article discusses these points in detail.

Choosing the Right Plastic Material

Material selection is one of the parameters that needs to be finalized before prototyping is commenced. Ideally, the material that is used for the prototype is the same material that should be used for the mass manufacturing process. Choosing the right material is important, as the wrong material can hamper the final product’s mechanical function, and overall application performance. To ensure that you choose the right material, there are two points that you need to consider.

1. Determine the Part’s Location and Application: The first thing you need to focus on is how the plastic will be used in the application. The questions that will come to mind are:
   • Do you require a single product, or need the product to be mass produced?
   • Will the part be installed within or outside the equipment?
   • If installed within the machine, then will the part be load bearing, or will it be used to support mechanical function.
   • If installed on the outside, will the part be required to have some aesthetic appeal?
   • Will the part be connected to larger components?
   • Do you require the material to have particular characteristics, like resistance to hot and cold temperatures, friction resistance, etc.?

   Getting specific answers to these questions will help you to finalize a material that will meet your requirements.

2. Choose the Right Material: Depending on the application requirements of the final product, the customer will have to decide whether to choose an in-stock material, or order a special plastic material. The following points can help you decide on the right material.
   • Availability: The shape and size that material is available in will help you decide on the right manufacturing process to use. If you are planning to use CNC machines, then it would be wise to choose plastic rods, pipes, or sheets. If you are thinking about using Fused Deposition Modelling (FDM), then you will have to consider printable plastic material. If you are planning to use injection molding, then you should look at Liquid Crystal Polymers (LCPs).
   • Prototyping Feasibility: CNC machining, injection molding, and 3D printing are also used in prototyping. Hence, you need to consider whether the chosen plastic material is suitable for the particular prototyping process. For e.g., ABS is a material that is more suited to 3D printing, while polypropylene is a plastic that is ideal for machining. If the material chosen will not be suitable for the previous two processes, then will it be suited to injection molding?
   • Material Recyclability: The recyclability of a material is extremely important, and has to be considered by the manufacturer. Most plastic products used in industrial applications today need to be either recyclable, or reusable. To ensure that the plastic can be reused or recycled, manufacturers usually recommend thermoplastics instead of thermoset materials.

Types of Prototypes

Today, manufacturers have the capability to create different types of prototypes, depending on the client’s requirements. If the customer has prior knowledge of this, it will be easier for him to work with the manufacturer in creating the final product. There are three types of prototypes that can be created by plastic manufacturers:

• Milled Prototypes: As the name suggests, this kind of prototype is created using CNC milling equipment. Generally, milled prototyping is used when the part in question has a complex design, and consists of several components. Also, CNC milling is used when the part requires functionality testing. The benefits of creating milled prototypes are:
  • Immense specification accuracy
  • Improved finishes
  • Fast feed rates

  The downside of these prototypes is that they can be quite expensive, as they require different types of machine tools, and lots of setup time.

• Working Prototypes: Also known as functional prototypes, working prototypes are created using plastic injection molding. A specialized mold with a single cavity is created for the prototype molding process. This type is used for industries like medical, and F&B. The advantages of this type are:
  • The process is extremely flexible.
  • Changes can be made to the prototype at the last minute before moving on to production.
  • Working prototypes are ideal for mass production.
• STL Rapid Prototypes: STL stands for stereolithography, which is a process used to create three dimensional objects by moving a laser along a mold, causing the liquid polymer to harden into the required part.Many customers prefer STL rapid prototyping, because it provides a variety of benefits:
  • It decreases development time
  • Complex models can be created
  • Costly mistakes are reduced extensively
  • It is easy to remove redundant features, and add in necessary ones in the design.
  • Marketing teams can look at the product design early, so that they can create sales and marketing strategies.

  However, like the other types, rapid prototyping also has its share of disadvantages:

  • The prototype can get damaged if exposed to moisture or sunlight.
  • Small or thin features may fade away.
  • Tolerances may not be exactly as per specifications.
  • Very few parts can be created using STL.

The key to creating a prototype that is feasible for manufacturing is to work with a knowledgeable, and experienced plastics parts manufacturer. Every detail, from the material to the prototyping method should be carefully discussed. Only then will you be able to move from prototyping to production quickly, efficiently, and cost-effectively.