Well, it depends on so many factors: design considerations, material, size, quantities needed, your budget. An expert will have to assess each product idea to decide the most effective and economically viable way of manufacturing it.

There's a vast amount of materials available for plastic injection moulding. A range of more common materials, but also things like antistatic plastic, thermoplastic rubber, chemical resistant plastics, infrared, biocompostable...and with colour compounding or masterbatch colouring you have an endless choice of colours as well. The moulding above is boring black, but it's made out of PPO - poly(phenylene oxide) - which is an extremely rigid and flame-retardant material.

Huge machines are needed to make plastic injection mouldings. Very large parts need an enormous mould tool and become very expensive to make, in which case a process like Plastic Fabrication may be a better choice, depending on the tye of product needed.

Often, several rounds of designing and modelling are needed before the go-ahead or production is given. Then, the injection moulding tool needed to make the mouldings will need designing & manufacturing. The mould tool is an intricate piece of work which costs manpower, material and many machining hours to make and represents the largest cost in getting injection mouldings. Of course, once it's all done, part cost is very low and repeatability very high for hundreds of thousands of mouldings.

In addition to a range of colours, the injection moulding tool can be made with a special finish which will show on the moulding. Just about any finish you like, for example leather look, soft touch, sparked, high shine, you name it. You can also have logos or other text engraved in the tool. Finally, you can have your mouldings printed, as a range of inks are available that will print well on plastic.

The process of creating a new product can be a very time consuming and costly process.  Here we will cover 3 basic aspects of launching a new product addressing an anticipated timeline and budget for each:

Toolcraft offer plastic injection moulding, vacuum forming and plastic fabrication, including a range of finishing, printing & packing services. Our longstanding experience allows us to help you choose the best manufacturing process for your new project. We also share our knowledge on our plastic moulding advice pages. Or just:

Plastic mouldings need very careful design to avoid tooling issues like undercuts (which will send up tooling cost significantly), locked-in features and not enough draft (What Draft Angles for Plastic Mouldings ?). The material and temperature will need to be taken into account in wall design, otherwise the mould may not fill fully. The placement of ejectors and cooling lines will need to be considered to ensure the product is aesthetically pleasing.

This blog series is for inventors and new businesses looking at creating a new product using the process of plastics injection molding.  It’s aimed at anyone with limited experience in launching a new injection molded product.

With a 3D part design in hand along with a proof of concept prototype you are ready to quote a mold.  The mold designer will need your 3D design files and will take those and may need to make some small adaptations to the part that will reap benefits when molded.  The mold designer will need approval for these changes and you can verify the impact on your parts with your industrial designer before approving the changes requested.

Prototyping generally takes two forms:  3D printing or short-run injection mold prototyping.  Accurate can both 3D print and create short-run tooling.  3D printing is a great medium for prototyping runs of 1-10 parts generally.  For prototyping runs of 50-100 or more parts, short-run injection molding tends to be more cost effective.  3D prints can have a turnaround time as little as 1-2 business days.  Short-run molds tend to have a lead time of 2-3 weeks minimum.  The advantages of a short-run injection mold are that it can be used for initial production and as well will offer much larger quantities of parts at a lower rate than 3D printing.

Once your mould tool is made, identical products can be made over and over again. And again. A decently made mould tool has a very long mould tool life, as long as it's treated well by the moulding machine setters !

The initial phase of creating a 3D design will mean employing an Industrial Designer who can turn your idea into a 3D rendering that can be passed along to a toolmaker for mold design.  At this time you may also look to take advantage of 3D printing technology to get a proof of concept.

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Cycle times can be as low as 10 seconds. Combine that with a multi-impression injection moulding tool and you get a LOT of products very quickly. That part above takes a bit longer as it's a specialist material and has a lot of features to be moulded correctly, but at about 50 seconds you'd still get 70 parts per cavity per hour. CNC machining a one-off would take half a day - 3D printing it even longer!

In Part 3, join us to learn more about how to make your parts and mold cost less, and how to ensure you have enough cash flow to start you project.

From product conception to final part can take months of design, testing and tool manufacturing. That said, if you know what you want, you can have the finished mouldings within 6 weeks. (Toolcraft's Chinese Mould Tools Flowchart shows how that could work). And as mentioned under advantages, once the tool exists, it takes very little time to run the mouldings, especially when you have a multi-impression mould tool. (Here's a list of Mould Tool Types).

Accurate can also offer some basic assembly and finishing services.  As a custom molder we can do assembly, decorating, inserting, drilling, and other services.  These services would be quoted on a per part basis upon request, usually at the same time as quoting the production of parts.

Terms usually include 50% due at the time of placing an order, 25% on mold completion, and 25% due upon approval of sample parts.

Accurate has an in-house tool shop and can quote your mold for tooling both in-house or made in China.  Tooling quotes usually take 5 business days due to the complexity of quoting a new mold.  We quote all large molds (for machines larger than 300 tons) using our Chinese supplier.  All other molds are quoted in-house unless requested.  Lead time on a mold varies greatly according to the current workload in the shop and the complexity of the mold.  In general lead times are 4-12 weeks and include the 1-2 weeks it will take to sample your mold.  Shop hours for mold makers are in the $80/hr - $125/hr range.  Molds can take 30-80 hours to build, or longer.

In summary ensure you have a few thousand dollars set aside for design and prototyping.  In addition expect a timeline minimum of 2-3 weeks plus revisions.

Plastic injection moulding is perfect for very intricate parts. Compared to other techniques, moulding allows you to incorporate more features at very small tolerances. Have a look at the image to the right. You can hold this moulding in the palm of your hand and it has bosses, ribs, metal inserts, side cores and holes made with a sliding shut off feature in the tool. That's an awful lot of features on a small part! It would be impractical to make using plastic fabrication and impossible to make using the vacuum forming process.

Industrial Design rates run from approx. $85/hr to $125/hr.  Most designers need at least 2 weeks to turn around a design with the number of hours required varying greatly according to the project and the number of revisions after an initial design.  Expect that your designer will need a few business days to quote your design work and to pay at least a 50% deposit to get started.  The balance will be due before you will obtain your design files.  Please note that you should obtain transferable files upon payment in full.  These are files with your design that can be revised by another designer if necessary and of which you have full rights to the design.

Plastic injection moulding advantages centre around great precision and high repeatability, combined with speed, a low cost per part and a huge choice of available plastics. Disadvantages include a higher initial cost and lead time than some other processes.

Parts production and secondary operations will be quoted in conjunction with your mold quote.  Upon approval of sample parts from your mold, the molder will be able to fulfill your orders.  The pricing of parts include: mold setup and take down, materials, labor, and machine hours.  For example:  Mold setup and take down might be $300, materials may be $.50/part, labor might be $20/hr, and machine hours might be $50/hr.  If your part has a cycle time of 30 seconds and is a 2 cavity mold then you make 2 parts each 30 seconds.  Thus over 10 hours you make 2400 parts.  The cost per part for an operator assisted production run would be:  $300 for setup + $200 for 10hrs of labor + $500 for 10 machine hours + $1200 for materials which is a total of $2200 or a per part price of $0.917.  If your order was for 600 parts your per part price would rise as the setup fee would remain the same thus your per part price goes to $1.00 for a production time of 2.5 hours.

Part repeatability is very high for injection moulding. Even the sprues and runners (the leftover bits of plastic created by the 'tunnels' through which the plastic material reaches the actual mould) can be reground and the material reused. You can explore this in more detail on our environmental impact of injection moulding page.

As a custom molder Accurate offers a wealth of experience in metal to plastic conversions as well as reengineering parts to eliminate gluing and other secondary operations.  Accurate is experienced with over molding and the use of blowing agents for thicker walled parts.  We would be happy to speak with you about the specifics of your project.

Whilst there is an initial high investment for the plastic injection moulding tool, after that the cost per part is very low. Other plastic processing techniques may require multiple operations, like polishing, whilst injection moulding can do it all at once. If you chose to CNC machine the part above, it would cost hundreds of pounds per part. If you're looking to go into full production, injection moulding is the way to go.

In summary, with a new product you will likely spend a few weeks and a few thousand dollars on design to start, a few thousand to tens of thousands for a mold that will take a month or more to build, then finally a few thousand dollars and a couple weeks for your first production run.  Accurate recommend starting a new project at least one quarter before you plan to begin production.