Onwards and upwards

As a contract manufacturer serving the highly regulated medical industry, and as a company keen to maintain its edge within a competitive global market, Carclo Technical Plastics (CTP) undertakes rigorous Continuous Improvement activities across a range of areas. This case study gives a brief overview of recent activities and the benefits which have accrued.

LEAN principles 

As part of a CTP-wide initiative, CTP’s Mitcham facility has led the way with adoption of Lean principles, utilising 5S and 6σ methodologies. The process has been led by senior management, including a master black belt practitioner and passed through the organisation to encourage complete employee ownership.

Following training of a majority of the facility’s workforce in 5S and 6σ white belt methodologies, CTP appointed a site-wide committee to develop this process further, training certain personnel to 6σ green and, ultimately, black belt levels. Individuals subsequently identified opportunities for process improvement and cost reduction. Several projects were identified and prioritised, led in each case by the specific instigator, and supporting methodologies such as Kaizen, Gemba and Muda have been introduced.

Gemba

In one example, inefficiencies were identified in the packaging and handling of work-in-progress (WIP) stock components between moulding and printing activities. The original procedure used disposable packaging to transfer WIP stock between manufacturing activities at CTP’s factory in Mitcham, UK. However, after a thorough appraisal of the process and product requirements, a solution was selected that utilised reusable pallet boxes. The optimisation of this activity has yielded cost savings of £4,625 (~€5,100) over eight months of implementation on one production line, with a projected annual saving of £6,939.

Kaizen

During a material variance green belt project at CTP Mitcham, a weakness in the packaging system of a bespoke automated production line was noticed, which led to a Kaizen project to optimise the entire automated manufacturing line. The project team used operator and technician feedback, as well as their own review of the current process to outline improvements, which were subsequently executed, monitored, and reviewed against the original process. These improvements increased the output per machine by almost 9,000 parts per day. CTP estimates additional annual revenues of approximately £190,000 from this project alone.

Process monitoring

As part of a major project to develop and scale-up manufacture of a drug delivery device in partnership with a global medical device company, CTP has invested significantly in advanced process monitoring equipment, as well as personnel training and development, aimed at improving injection moulding process control and reducing costs of Quality Assurance (QA) and waste.

CTP has constructed a new production cell, with 14 FANUC all-electric injection moulding machines, each equipped with six-axis robots, bespoke end-of-arm tooling (EOAT) and RJG’s e-Dart process monitoring software, allied to in-mould pressure transducers. The pressure sensors are located in each tool with corresponding hardware and software incorporated into the moulding machines. These sensors provide output data for peak cavity pressure, hold pressure, hold time and back pressure. These parameters are measured and recorded from each cavity for every injection moulding cycle. These data can then be used to plot a graphical depiction of individual cavity conditions during every moulding shot, thereby generating trend data that can be viewed as the fingerprint of the injection moulding process – because precise information about the conditions within each cavity of the tool is available.

Not only does this offer increased clarity about the quality of the moulding process for individual components manufactured, it effectively enables 100 per cent inspection to be achieved without requiring any human intervention. In contrast, to achieve 100 per cent inspection from conventional process monitoring methods is extremely laborious and costly.

CTP has made widespread use of these technologies through the process development and validation phases of this project, supported by existing metrology and statistical analysis using commonly available tools. CTP is now able to achieve an added layer of process monitoring beyond the current capabilities of the standard injection moulding process, by providing live and retrospective data, showing accurate injection moulding process parameters from individual cavities during each cycle.

CTP’s experience of using cavity pressure sensors has given the company the confidence to scale back the frequency of metrological inspection of the products manufactured in the new production cell. This has resulted in reduced production labour costs associated with quality control activities during standard manufacturing operations such as in-process inspection and the material scrappages associated with sample collection for this activity. This is a direct consequence of achieving tighter control on the quality of the parts produced. In addition, the reduced need for human intervention during routine production also significantly decreases the potential for outside contamination to occur. Most recent quality data reveal an 80 per cent reduction in non-conforming products attributable to part quality since the introduction of the cavity pressure sensors, across all production lines utilising this technology. CTP has also observed a notable drop in overall scrap rates from production activities in this manufacturing cell.

Other than the reduced labour costs CTP is now able to offer, the company anticipates that substantial savings will be accrued over the lifecycle of this contract, including a reduction in the cost of non-quality. If one considers an estimated average cost of each non-confirming batch of product to be between £40,000 and £100,000, the benefits are clearly significant. Although the initial investment in the process monitoring equipment is high, the main return on this investment to CTP’s customers lies in minimising the QC and QA cost of human intervention, targeting zero defect supply of product and ultimately, cheaper product unit pricing long term. CTP is able to benefit from utilising these technologies by improving injection moulding process control, lowering personnel costs and optimising overall production process efficiency, allowing CTP to remain competitive on both the quality and pricing of the products the company delivers to its customers globally. In parallel, CTP’s commercial partner in this project, assessed several of CTP’s global manufacturing facilities as part of its own vendor management program and is highly supportive of CTP’s Continuous Improvement activities, rating CTP among its leading global vendors.

Preventative maintenance

CTP Mitcham recently purchased an i³ MicroClean dry ice blasting machine from Cold Jet. This non-abrasive tool cleaning method utilises compressed air and fine ice particles to clean gas build-up produced during the moulding process. CTP is currently able to perform in press cleaning on both the fixed and moving half of mould tools, and the cleaning process can be performed whilst the tool is still hot, with no detriment to polished surfaces of the cavity or tool. Since the introduction of the ice cleaner, CTP has been able to reduce in-press tool cleaning time on average from four hours to 45 minutes per tool, whilst also reducing preventative maintenance time in the tool room. Consequently, CTP can now produce more parts since tool cleaning time and frequency have been significantly reduced, therefore increasing the available production ‘up-time’ for the respective tools.

Conclusion

By definition, the process of Continuous Improvement never ends. Carclo Technical Plastics has introduced a number of initiatives, aimed at delivering Best-in-Class performance with measurable benefits to its business and customers. While progress has been acknowledged by a world-renowned customer base, the process continues.