Back in 1979, an entrepreneurial greengrocer diversified into selling plastic packaging, which eventually became more profitable than ensuring Staffordshire residents were getting their daily portion of healthy eating. This soon set the foundation of Kenson Industrial Plastics Ltd, a company that evolved from healthy eating to packaging, and then on to the trading of plastic rods and tubes.
Just a few years after the company was founded; a young machinist, Kevin Hutcheson joined the company. The son of the company founder and now the Managing Director, Kevin re-directed the business into machining plastics and the modern face of the Cannock based company now has a host of CNC turning centres that includes its latest acquisition, a Tornos DT26 turning centre.
Kenson purchased its first CNC machine over 25 years ago to complement its capstan machines and now the business employs nine CNC machines that include HAAS, Hurco, Mazak and CMZ CNC milling and 65mm diameter capacity turning centres. Machining spacers, rollers, washers, threaded gears, insulating pads and machine guarding from materials such as Nylon, Delrin, Ertalyte, Polyethylene, PVC, PTFE, PEEK, Torlon, Vespel and other plastics, the ISO: 9001 company produces anything from small batches up to production runs beyond 10,000-off. It is here that the Tornos DT26 has made all the difference.
The four employee company won a contract to manufacture gear motor components in batches of 10,000 per month and this instigated the search for a new turning centre. Prior to buying the Tornos, the monthly quantity was tying-up one of the company’s 65mm capacity single spindle turning centres for 3 weeks every month. The small subcontractor wanted to free-up capacity on its 65mm machine and produce parts faster to prevent any potential supply chain issues.
Commenting upon the search for a turning centre, Kenson Industrial Plastics Managing Director, Mr Kevin Hutcheson says: “The parts being machined are only 12mm diameter. We looked at all the sliding head suppliers as well as a few other options, but the Tornos DT26 fitted our business perfectly. Other sliding head suppliers recommended running neat oil, which is standard for sliding head machines. However, Tornos said we could run the machine with either soluble or neat oil and as we machine plastic parts, we don’t want staining from oil, nor do we want to clean oil from plastic parts. Tornos had instantly tipped the scales in their favour.”
With five linear axes and two C-axes, another beneficial feature on the Tornos DT26 was the integrated 20 bar pressure coolant facility with a high-pressure air blast. “Having such features integrated into the Tornos as opposed to optional extras reduced both the machine cost and footprint. The combination of a smaller footprint machine with integrated features and the soluble oil aspect had swung us towards Tornos. We preferred the Tornos DT26 for these aspects but it was also the ease-of-use, machine kinematics, simple set-up tooling configuration and also the fact that Tornos are very local from a service perspective that sealed the business.”
The machine instantly slashed the cycle time of the Ertalyte TX plastic gear components from 50 to 25 seconds per part, taking more than seven days off the previous monthly production schedule. Additionally, the facility to work with and without he guidebush has reduced material consumption and with a changeover time in the region of 15 minutes, the customer can rapidly switch between modes to suit each batch run. Historically, Kenson has only operated on a single 8-hour shift basis; however the Tornos DT26 has been supplied with the 3m barfeed and the Tornos Active Chip Breaker (ACB) system for lights-out machining. Referring to this, Mr Hutcheson says: “We’ve only ever run day-shift machining, but now we have the Tornos and its ACB system, we can look at unmanned running. At present, the DT26 has halved our production times and freed capacity of the turning centre that was running the gear project. Additionally, the DT26 has replaced an ageing EMI-MEC automatic turning centre and comfortably absorbed all the work the EMI-MEC was previously machining. For example, the production of 2,000 small rollers on the EMI-MEC machine would take 3-4 days; the Tornos produces four rollers a minute, meaning the job is finished in a single-shift. This machine was also dedicated to producing 3,000 spacers each week for electrical cabinets; we now produce these parts on the Tornos at least 50% faster than ever before.”
The Tornos DT26 has completely changed the way the subcontractor schedules its work, as Mr Hutcheson says: “We have a monthly order for 2000 nylon conveyor belt parts with a previous output of 400 parts a day; this would tie-up one machine for more than a week per month. The Tornos can do more than 1000 parts a day, so we will produce 6000 in a week and hold the quarterly stock for the customer. There are many examples of how the Tornos has more than halved cycle times, however the key aspect is that the machine has freed capacity from all our larger turning centres.”
Kenson is building its confidence towards lights-out machining. When the company targets round-the-clock running, the Tornos is likely to improve throughput and capacity availability significantly on all machines. As the first turning centre with a twin-spindle, the DT26 has reduced cycle times on more complex work. Referring to this, Mr Hutcheson says: “We were apprehensive about the step to a twin-spindle machine but the Tornos TISIS software really simplifies the process. TISIS allows us to do a simple program for the main spindle and another program for the sub-spindle, once we have these foundations in place, TISIS prompts us to fill-in the remaining movements between the spindles. Furthermore, the machine operates with a FANUC 31 Series CNC control unit that is familiar with all our machinists.”
The sub-spindle operation has improved precision, consistency, surface finishes and overall component quality whilst the TISIS system has simplified programming processes. However, it is a smaller feature on the DT26 that is saving considerable time for Kenson - the part-catcher. “Plastic swarf is often long and stringy and without a part-catcher on our other machines, small parts would drop into the machine sump, leaving staff in a rescue attempt to redeem parts from the swarf. The Tornos DT26 efficiently collects the parts and puts them into a bin outside the work envelope – it’s surprising how much of a difference some of these peripheral features can make to the everyday life of the machinist. We’re delighted with the Tornos, it’s been a great addition to our facility,” concludes Mr Hutcheson.