Lead time is always a significant factor in all of manufacturing. It is the amount of time allotted from conception up to the completion of any project. We have already discussed the importance of lead time in our past blog posts and there is no need to divulge furthermore details around the concept. In this wiki post, we will focus on lead time on plastic manufacturing particularly the amount of time it takes for injection molding. If you want to learn about injection molds in general, check out this BBC video.
Lead time for injection molding vary due to a lot of factors such as complexity or simplicity of the plastic product design, efficiency of the plastic injection molding company, advancement of the plastic injection molding machine, and a lot more. This is the same reason why plastic injection molding companies always ask for the product design from the client before they are able to state the cost and time needed for completion. They do not have a standard timetable for plastic designs due to variations and possible intricacies involved for each.
Injection molding is a time consuming process and it is not a regular task which can simply be done overnight due to the mold that usually has to be carved out of metal. For some, it may even sound so complicated since it is a process only done in plastic manufacturing companies and close to impossible for a DIY method or rudimentary practice. The features on a plastic component all add up to the amount of time needed to create its mold and the style or approach may tend to vary from straight pull design, fabrication and its build.
Examining the Injection Molding Process
Before the injection machine is revved up for its function, a concept or design has to be in place before the molds are created. Molds creation starts from having a concept much like any process in the world of manufacturing. With the design and concept in place, the plastic mold manufacturer can now assess whether this plastic part can simply be created by the regular straight pull method or any other approach.
The straight pull method is done by pulling the opposite halves of a mold apart. Component features can now be added through approach such as undercuts and threads. These different approach are used to add common features to plastic parts such as hydraulics and slides. However, keep in mind each feature adds up to the complexity of the design which translates to longer lead time.
Another big factor not only to the lead time but as well as cost of creating molds is the geometry of the plastic product design. Even the slightest angle which alters the overall shape of the design will greatly affect the mold for it. Unless the plastic product comes in a basic shape, then this should be not much of a deal. Geometrical factors such as shape and symmetry impacts the entire injection molding timeline and costs.
It would be safe to assume plastic injection tooling would take as quick as a couple of weeks up to two months depending on the factors mentioned beforehand.
The best way to cut down lead time for injection molding is to cooperate and work hand-in-hand with your injection molding manufacturer. Having clear communication lines will help the plastic injection molding company accomplish your mold easier and at the same time make sure your requirements and specifications are met. Being open and attentive to your injection molding manufacturer will not only cut down lead time but also help reduce injection molding costs.
Standard Lead Time for Plastic Injection Molding
As mentioned above, plastic injection molding lead time vary due to a lot of factors. However, it is safe to come up with standard lead time for different plastic products given a traditional setting and regular approach.
Single cavity and single gate molds with minimal ejectors and a simple cooling port will normally take two or three weeks to make given a low production volume of 10,000 units max. Any volume which exceeds the 10,000-unit mark will already increase lead time up to a month or so regardless of the simplicity of the plastic mold design. This is due to the fact that you are liking doing only a few numbers of cavities. The cycle time for making one plastic piece is about 30 seconds and you can do the math yourself that it takes quite long if you only have 1, 2 or even 4 cavities that work at the same time.
For molds with multiple cavities and multiple gates along with several ejectors, moving parts, specialized surface finish, complex cooling ports and high dimensional tolerances; it may take a month up to 2 months to complete these type of molds and production runs. High production volume will further increase lead time for injection molding as it has always been a factor for time completion.
When it comes to massive plastic manufacturing, most plastic injection molding companies use softer metals as they are easier to deal with mechanically for the injection machine and has a quicker cooling time. Hard steels are ideal in terms of quality and durability but the entire injection molding process slows down and not to mention the hefty price which comes along in purchasing hard steels.
The usage of thermoplastics and thermosets for injection molding will also affect lead time of plastic manufacturing process. However, these factors are too complex on their own and deserves a separate wiki article to cover such topics in the future. The history of injection molding has brought enormous progress and it can be expected that things will continue to become easier.