Design Tips

Several Tips on saving injection molding cost


I prefer to know the intention of the design before getting the client a free quote, which structures are necessary and critical, which are not. It helps us finish a cost-effective quote for the client. Here are several tips on saving injection  molding costs.

A. Tool direction and PL line.

1. Make sure the directions of reinforced ribs, snaps, bumps are in line with tool direction to avoid adding core pulling mold sections, to reduce joint lines, and thus to extend the mold life. Also, we should make sure no undercuts in the tool direction

2. Consider PL line on a flat surface first rather than slopes or stepped surfaces.

B. Tolerance

Make sure if all tolerances in 2D drawing can be achieved. Better mark up which tolerances are critical. If the part is to be assembled, please provide your mold supplier with assembly CAD drawings. Looser tolerance, cheaper price.The higher SPI polishing grade you require, the more expensive mold you get.

C. Layout and mold life

Using multi-cavity and family molds if the part size is small or if there is a large annual need. It will increase the mold cost for a single part, however, it can reduce the part cost.

Mold life 5000 and mold life 100K have different requirements on mold materials and slides, which leads to different costs, please inform your injection  molding supplier of the mold life before quoting.

D. Materials

Using materials that are just okay for your application but don’t luxuriously exceed your actual needs.If Chinese domestic ABS material is enough for the injection molded part, no strength requirement, don’t ask for a quote on imported nylon glass fiber-filled resin which would significantly increase the unit price.

E. Simplify Some structures.

1. Add radius instead of straight corners

2. Use kiss-offs instead of shut-offs

3. Use shut-offs on core and cavity instead of internal undercuts.

4. Shut-offs need to be as obvious as possible, generally speaking, the shut-off should be with a draft 3°or ≥0.2mm plastic.

5. Get rid of structures that need secondary processes (post-injection  molding process) like custom-made inserts. (Getting rid of painting or plating on the product can save the cost as well)

6. No textures and no molded part numbers can save your cost too.

F. Holes

1. Shape of the hole needs to be as simple as possible, normally make it round.

2.  Axis of the hole should be in line with the tool direction, in order to avoid adding core pulling slides

G. Radius.

1. Radius should not be too small because a smaller radius would cause concentrated stress both in the product and the mold, might cause cracks on the product and the cavity.

2. Proper radius would improve the machining process. Removing sharp edges of the product can also allow us to CNC the part rather than go for an EDM process.

H. Considering the next tool modification into the initial mold design.An exchangeable insert would help save the cost of making a new tool.

I. Molds stay with your Chinese manufacturer rather than being imported to your local manufacturer. We apply the Chinese standard LKM for the former option, DME or Hasco standard for the latter option which increases your expenses.

Either it is a rapid tool to test the market or a production tool to move forward, if you have questions on design for manufacturing, drop us an email ( RM Mold will be the right solution provider, just for you.

PREVIOUS:Design Tips on reducing unit price of CNC machining

NEXT:RM Mold is ISO9001 and ISO14001 certified

Leave a Reply

+86-755-23215064 English



Leave a message