Injection moulding process improved with the award-winning training programme

Injection moulding process improved with the award-winning training programme

Polymermedics Ltd in partnership with G&A Moulding Technology Ltd accomplished the 2 year-long training programme for all members of the Technical team. Entire injection moulding process was optimized: as the result of the training, we gained the industry’s top level of OEE, improved the tool validation process, reduced the scrap rate and our carbon footprint. For its significant impact, our programme was nominated for the annual Plastic Industry Awards of 2012.

I. Scope & background

In 2009 Polymermedics Ltd (formerly Polymeroptix UK Ltd, part of the West Pharmaceuticals Group) embarked on a programme of training in partnership with G&A Moulding Technology Ltd to increase the skill level and approach of all its Technical Staff.

“In order to make the plant more profitable and efficient something needed to be done to address this and bring stability to the manufacturing processes”

All members of the Technical team had previously been trained in generic injection moulding techniques which focussed on the wider needs of the plastics industry, with no focus on the intricacies of the mould tools and processes within this manufacturing plant. The skills learnt with this type of training were quickly lost when returning to the plant as it was too easy to slip back into previous bad practices and forget what had been taught.

Also, with new KPI’s (Key Performance Indices) being put in place the plants overall equipment effectiveness and scrap levels were not in control and in order to make the plant more profitable and efficient something needed to be done to address this and bring stability to the manufacturing processes.

The management team of the Plastics plant decided to try a different training approach and discussed these options with G&A and the offerings that they had were a perfect fit for the direction that the business wanted to go in.

II. Training Requirements

Key Deliverables from Training

In order to deliver real tangible benefits from the training the following points were deemed the key deliverables of the training:

  • 1Project based approach to build process ownership and greater understanding across the technical team
  • 2Drive results with defined, tangible & sustainable process benefits
  • 3The objective of each improvement project was to return more financial benefit to the moulding division than the cost of the training required to improve the process.
  • 4Develop a core of highly skilled “Process Technicians”.
  • 5Promote and create an analytical and statistical data-driven approach to process improvement issues.
  • 6Eventual reduction in time spent on process issues, therefore creating time to prevent rather than cure (proactive instead of reactive).

Training

The training was delivered over the course of 2 years with all process technicians being moved to a dedicated shift pattern to enable training to be delivered and the time to put what was learnt into practice. All Process Technicians were given injection moulding processes to improve with the objective of improving performance capability, component quality, overall equipment efficiency (OEE) and raw material utilisation by reducing downtime and scrap, which gave ownership to them for these processes.

The programme of training was given in stepwise blocks, commencing with a detailed understanding of the basic constituents within the injection moulding process.  Upon fully understanding these principles, a series of modules were delivered covering in detail the important elements:

  • 1Melt Preparation and Plasticisation involving the important process parameters utilised to convert the polymeric material from its solid to a uniform (homogeneous) molten state.
  • 2Process Control Technology covering how the molten material is introduced into the mould cavity upon achieving melt homogeneity and achieving dimensional attributes and surface quality requirements as well as end surface performance.
  • 3Coupled with these principles was the differentiation of the types of thermoplastic materials and the manner as well as process parameter selection required to ensure optimum performance from the process as well as the product.
  • 4Understanding equipment performance requirements and the interaction of the injection moulding machine, mould tool and ancillary equipment with regard to specification and performance expectancy.
  • 5The final module provided a detailed understanding of how to use a systematic procedure to fully optimise the injection moulding process, enabling involvement and correct utilisation of the influencing factors and the correct selection of process parameters for effective component production.  Upon achieving an optimised process, fully assess its capability and create a window in which selected process parameters could be altered without affecting the quality requirements of the mouldings.

During and after each module, each technician was expected to implement the knowledge gained and the results of their efforts measured in terms of performance outputs.  The format of the training programme was based upon 30% theory and 70% practical. Project work and tasks between modules at selected timescales within the programme workshop and/or clinics were arranged to discuss the outcome of the project work and address any issues.

III. Training Results

OEE

Below you could see a graph of the OEE from 2008 to 2011 showing the rising trend. Polymermedics gained World Class manufacturing levels.

OEE-Polymermedics

Scrap

With the reduction in scrap rates year on year since the training began we have managed to reduce the number of scrap components be sent from the plant as waste. Our scrap has reduced by approximately 3.2t per annum.

Scrap, Polymermedics

IV. Other Benefits from the Training

Power Saving

With the new found efficiencies and the fact that we can produce a bigger number of parts on fewer machines this has had a positive impact on the amount of energy required to produce parts. Taking averages across the plant, we have managed to reduce the annual consumption annually as shown in the table below. This has not only managed to prevent our power costs increasing due to the price hikes that energy companies have been giving to customers but we have reduced our carbon footprint which is helping us to meet the criteria for the ISO 14001 accreditation.

YearKWH Per Annum Reduction KWH
20083200037
2009318658813449
20102813804372784
20112619650194154

Validation

Not only have scrap rates reduced and OEE levels increased, Polymermedics also improved the tooling validation process. We have incorporated the G&A PRO-OP into all new tooling validations and tooling verifications to ensure that the tool is absolutely as it should be. In previous years there has always been the discussion with the toolmaker as to whether the tool is at fault or the process. This is no longer the case. As we can guarantee that the process is stable we can highlight much more effectively tooling issues that are apparent and make tooling modifications knowing the outcome. Reducing time and cost when validating new tooling.

“In 2008 Polymermedics produced approximately 1.3 billion parts from a fleet of 28 moulding machines. In 2011 we produced 1.5 billion parts from 18!”

V. Conclusions

The training programme that we have embarked on has shown massive benefits to our processes and efficiencies. We now have a skilled technical workforce who all have the same understanding of injection moulding processes and tools and who all approach problems in the same way.

In 2008 Polymermedics produced approximately 1.3 billion parts from a fleet of 28 moulding machines. In 2011 we produced 1.5 billion parts from 18! This has enabled to business to become more cost competitive and reduce operating costs due to the reduction in power usage to produce the parts, less scrap and less material usage. Without this training the business would be in a much more dire position and with the current economic climate potentially not in business.

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