The Injection Moulding Process

The injection moulding process from concept to product can take anywhere from 3-12 months. This is dependent on the type of product, the design, its complexity and the volumes required (including machinery that may need to be purchased) to complete the process.

The injection moulding process can vary depending on the client requirements and the final product use. Whilst some projects may be completed within a very short timeframe, larger more complex projects require more time and effort to be completed.

Outlined below is a simple flow chart which explains all the required steps to follow during the injection moulding process:

1. Concept thought – Great ideas aren’t worth much if there is no execution. Some of the best ideas we have come across have been drawn up on a napkin and brought in to SDI Plastics, whilst other clients have come in with a concept prototype already complete.

Either way, once all confidentiality formalities are completed, our team begins to understand and gather critical information about the product, its use and the entire project. Things such as volume, target pricing, distribution and type of plastics to be used are discussed. A quotation to commence the work and receive approval to continue are requested here.

2. a. Once fully briefed, our design team begins the work of formalising the client ideas into a design ready for injection moulding. This is created by using 3d design software such as Solidworks & Mastercam to create a 2 dimensional drawing of the product.

The image below represents a 2 dimensional drawing with a range of measurements.

NB: This is a very important part of the process and revisions can be costly if this part of the process is not executed correctly. Our clients are encouraged to check the design, prototype and 2d measurements to ensure they are fit for purpose.

b. Once this drawing has been approved, we then move onto the model of the product. This is an important step as the model is used when designing the tool. It helps to negate any problem areas of the part design in the injection moulding process.

When this process is complete, our clients are able to view this product using their own software or a free viewer that is available for download. Below is an example of a 3d model once the 2D is approved.

c. From here it is up to the client whether or not they want to build a prototype. In 60% of cases clients choose to go ahead and prototype the parts.

The remaining percentage choose not to for various reasons including costs, confidence in our design, and no actual need for it.

Prototyping can typically take anywhere from 2-3 weeks. An example of a prototype is below. This is to ensure the part and all of its components (as the above examples show) fit correctly.

3. Once we have received sign off on the 2d drawing and model and/or the prototype and quotation for toolmaking and part price, we then begin the process of toolmaking.

Throughout this process the toolmaker and injection moulding technician work closely to ensure the tool is made correctly.

At SDI Plastics we continue to liaise with the design team with discussions such as ensuring the right type of steel in the mould is used, checking the cooling is optimised, ensuring the right ejection system is being utilised and the gating and venting is in the right areas (just to mention a few.)

Ensuring these points are completed according to the design and specifications is vital. We know that a correctly built mould will last our clients for decades and more than last the products lifecycle.

“We design and build tools to stand the test of time. Our high quality tools will help you succeed with your product and will last for decades.”

Kulbir Dhanda, Director, SDI Plastic

Typically an injection moulding tool will be made of hardened steel, though there are occasions where we may recommend the use of an aluminium tool (for example a low volume product.)  In these instances the process looks very similar, with a simple substation of aluminium for hardened steel.

An example of the toolmaking process is below:

The start to finish process depends entirely on the complexity of the product, however a standard injection moulding process including a 3D prototype typically looks something like the below:

Week 1 to 2

  • Information gathering
  • Quotation for design, toolmaking and part price submitted for approval
  • Initial 2d product design created
  • Sent to customer for approval
  • Revise and design (if required)
  • Initial product design approved by customer

Week 2 and 3

  • Design team creates 3d model of part
  • Sent to customer for approval
  • Revise and design (if required)

Weeks 4 to 7**

(if prototype required)**

  • Building of prototype
  • Send to customer for approval
  • Revise and design (if required)
  • Prototype approved by customer

Weeks 7- 18

Design team, injection moulding technician and toolmaker have final meeting regarding
optimizing the product for injection moulding

  • Design team designs a 3d model of the mould used to create the product
  • Send to customer for approval (if required)
  • Toolmaking begins

Weeks 18 to 20

Commission mould (ensure it works as designed

  • Testing of trial product
  • Send to customer for approval
  • Revise (if required)
  • Trial product approved by customer
  • Production commences

A relatively simple mould that doesn’t include the 3D prototype typically takes 8-12 weeks. More complicated moulds that also include the 3D prototype can take up to 16-20+ weeks to get to the product stage. In any case, we create a project timeline and stages for each individual project and communicate openly with the customer to manage their expectations of cost and timeframes.

We take special pride in the fact that we work to our timelines and take steps to avoid any delays.

“At SDI Plastics, we always meet our deadlines and take accountability for our projects.”

Kulbir Dhanda, Director, SDI Plastics

Budget constraints pending, we can make pretty much anything. Over the years we have built parts ranging from camera lens’, golf tees, food containers, electrical components, fence caps through to bigger items like a go kart and other sundries.

How much does injection moulding cost?

The cost of the injection moulding process varies for each project, depending on the specifications. We will always run you through the costs and we also offer payment terms if they are required. In most cases, because of the sensitivity around the product, we sign a non-disclosure agreement with our clients at this stage.

“We pride ourselves on the fact that everything we do is 100% confidential.”

If you have any questions about the injection moulding process or would like to get a competitive quote for your project, please feel free to contact us or one of our representatives for a 100% confidential discussion about your product.

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