Question 1

Can plastic injection be replaced with 3D printing ?

Accepted Answer

The development of small quantity but diverse plastic products has gradually becoming a trend, and the trend of 3D printing has also become popular. People often ask whether 3D printing can be replaced plastic injection?

Both 3D printing and plastic injection can be used in the manufacturing of plastic products, but the practical application is quite different. When evaluating whether a plastic product should be manufactured by 3D printing or plastic injection, let us first understand the differences between these two processes:

1.Differences in principles of the manufacturing process
The principle of plastic injection molding is like making chocolate. After heating and melting the raw materials, pour them into the mold, and then demold after cooling, and the finished product is completed. You can also add different color pigments to the material to make chocolates of different colors.
The biggest difference of 3D printing from plastic injection is that it does not require a dedicated mold, just like stacking building blocks, which are stacked layer by layer. Because there is no restriction of the molding mechanism, the creativity in product design is virtually unlimited, and products of any shape can be achieved. For example, 3D printing can produce closed hollow products, but plastic injection cannot.

2.Differences in production efficiency
Although 3D printing can save mold costs, its mass production capacity is far lower than plastic injection. For a product the size of a pencil holder, 3D printing takes at least 2 hours to produce, while plastic injection takes less than 2 minutes.

3. Differences in the detail of appearance
Since 3D printing is stacked layer by layer, there will be fabric-like fine lines on the surface of the product. The plastic injection can achieve a specific texture or mirror-like smooth product surface.

4.Differences in structural strength
Injection molded products are usually more resistant to drops and impacts due to the tighter combination of plastic raw materials, while 3D printing is relatively fragile.

5.Differences in the costing structure
In the initial development cost of plastic injection, mold costs are relatively high, but raw materials and molding costs are low, while 3D printing is a one-time custom cost, and a product may cost several thousand Taiwan dollar to tens of thousands of Taiwan dollar.

Simply put, 3D printing is a proofing process, and plastic injection is a mass production process. If you want to create a unique product, you can choose 3D printing, but if you need mass production, you need to choose plastic injection.
The current 3D printing technology cannot replace the mass production capability of plastic injection. Therefore, the foreign customers of 3D printers on the market are also produced by plastic injection. But if you only need a very small amount of finished products, or need to verify the product design, 3D printing is a good choice.

Question 2

Four key points in acquiring an accurate quotation, first time and every time

Accepted Answer

A difficult problem often encountered by buyers of plastic products is that they do not know how to make manufacturers quickly and clearly understand their inquiry needs and produce an accurate quotation. Here are four key points of inquiry to help you communicate with the injection factory quickly and effectively.

Provide design drawings or samples

Provide 3D drawings, so that the manufacturer can understand your product design at a glance. Provide 2D drawings, and mark the dimensions and tolerances on the drawing surface, which can allow manufacturers to meet the accuracy requirements of the product. If there is no 3D drawing or 2D drawing, please provide at least a sample so that the manufacturer can have a basis when evaluating the price.
When the purchaser only provides a product photo, and hopes to obtain an estimate of the mold cost and the injection cost. For the manufacturer, since the size, accuracy and other information of the product cannot be ascertained, even if it can provide the quotation, it will not be accurate. An inaccurate quotation, does not have much reference value.

Specify which raw plastic material to use

Raw Material is one of the key costs of plastic products. There are dozens of common raw plastic materials on the market, and the prices are very different. If you cannot specify which raw materials to use when evaluating the price, it is difficult for manufacturers to provide an accurate quotation. When you are not sure which material to choose, you can provide information about your product's function, use, demand, etc., and let the manufacturer assist you in evaluating it and giving you raw material suggestions. However, which raw material is most suitable to the product is ultimately a decision the product designer/developer needs to make.

Provide product appearance requirements

The color and surface roughness of the product are the key to in determining the product texture. If your product wants to show a sense of technology (such as electronic products, mobile phone cases, etc.), you may choose a high-gloss surface to show the texture of the product. And if your product wants to be resistant to wear and dirt (such as hand tools, plastic parts, etc.), you may choose to use coarse bite surface (bite flower) to increase the Abrasion resistance of the product. Alternatively, the appearance and texture of the product can be improved through surface processing methods such as painting, printing, electroplating, and bronzing after injection molding.
Different appearance requirements will affect the cost of mold design (biting), the cost of secondary surface processing (painting, electroplating...), and the yield of products. In addition, different product appearances will also affect the packaging and delivery ways methods (for example, for the more delicate, non-abrasion resistant and non-scratch resistant products, packaging with better protection for the product is required, due to this factor, the packaging time and cost, and the selection of packaging materials will vary).

The minimum order quantity

The production cost of producing 500 pieces at a time is different from producing 3,000 pieces at a time. Therefore, the minimum order quantity (that is, MOQ) is one of the important information for manufacturers when producing quotations. For plastic injection, assuming that the minimum production time is 8 hours each time, the total number of seconds is 28800 seconds, and the production time per mold is 45 seconds. For a mold with two cavities, the MOQ is 1,280. Since the production time of injection molding not only consists of the actual mass production (machine operation) time, but also the time of various praparations such as the installation of mold and the uninstallation of mold. Therefore, it is not difficult to see that when the production quantity increases, the average cost per product will decrease. This is also why, when the order quantity is too small, the quotation you get is usually quite high.
Information on the Internet is vast and easily attainable, and you can easily find many manufacturers to inquire and compare prices, but only by providing complete information and adequate communication and explanation can the results of the inquiry be of reference value.