Replacement sliding headstock lathes increase turn-mill capability
The decision to invest in new machinery can be difficult, especially when existing equipment is still working reliably. But technology is changing at an alarming rate, so you could really be missing out. PES reports.
Good quality machine tools operate reliably and retain their tolerance for two decades or more. The problem is that technology changes so quickly over such a long period that the productivity of older machines cannot match that of their newer counterparts.
This was the situation Redruth’s sub-contractor DP Engineering found itself in until it purchased three new Cincom lathes from Citizen Machinery UK. It is an L20-XLFV installed three years ago, an identical machine which arrived in the fall of 2021 and an M32-VIIILFV purchased at the end of last year. These last two machines were direct replacements for the similar type 20mm and 32mm equivalent capacity sliders and were purchased at the turn of the millennium, several generations of machines ago.
Philip Anthony, Sales and Marketing Manager of DP Engineering comments: “The faster rapid strokes and the higher power and speed of the main and secondary spindles and driven tools on the new lathes have increased our capacity significantly. A stainless steel aircraft part previously we were shooting in one shot on an L20 that is over 20 years old now takes half that time to produce on its modern replacement.
“It’s a similar story on the 32mm machine, which is more user-friendly than the older generation lathe and offers better access and visibility into the machining area. Plus, the addition of a rotary B-axis on the train tool holder allows us to machine more complex parts than was previously possible on our sliders.”
LFV tool oscillation for automatic chip breaking
A notable technological advancement from Citizen since DP Engineering bought the first Cincoms was the introduction five years ago of its proprietary LFV (low frequency vibration) chip breaking software running in the Mitsubishi control. This results in a significant increase in productivity when machining malleable materials such as titanium and stainless steel.
This is particularly advantageous for the subcontractor, since a third of its turnover is made in the aeronautical sector where the use of such materials is common, as is the case in the medical industry, which has also generated more work since the start of the Covid pandemic. Normally, when machining, stringy chips often become entangled around the tool and component, potentially damaging them and requiring the lathe to be stopped to clear them from the machining area.
Mr. Anthony explains: “The first L20 we purchased in 2019 is equipped with an LFV. We knew the technology and sent a team of engineers to Citizen Machinery’s Brierley Hill center to see demonstrations of the chipbreaker feature in action.
“For certain parts of cycles, it is very effective in ensuring that what usually becomes a bird’s nest of chips is broken into shorter chips, avoiding having to stop the machine to remove them and the consequent loss of production. results.
“The best part is that LFV can be programmed to stop during a cycle when not needed by inserting a G-code, minimizing the slight reduction in metal removal rate during times when the tool wobbles away from the surface of the component to break the fries.
“On some jobs, even when cutting stainless steel, we don’t need to use LFV at all. It depends on the design of the component, the tolerances to be met and the tooling used. It’s fantastic to have it there for when we need it.”
He added that, in practice, the LFV is particularly effective at controlling chips on the L20s during turning and drilling operations, while on the M32 it speeds up roughing and also plays a role when tapping. Overall, full control of chip generation ensures that processes are more reliable and repeatable, in addition to which tool life is significantly increased.
Operation without guide sleeves reduces costs
Another attribute of the latest three Cincom lathes that increases their versatility, besides the long spindle uptimes and unmanned operation made possible by the LFV chipbreaker software, is the ability to turn-mill shorter components in fixed head mode without the guide bush, which can be removed and replaced in half an hour.
This allows the use of lower quality unground bars, increases the maximum diameter of stock that can be accepted by several millimeters and also reduces wastage of bars due to much shorter drop lengths. Consequently, this mode of operation is frequent in the Redruth factory, in particular for the large volume of Kanban production carried out by DP Engineering for its customers.
Mr. Anthony commented that overall, considering the higher machining speed, LFV chip breaker function and guide bushless operation option, the last three lathes offer DP Engineering not only considerably higher productivity, but also much more flexibility when allocating jobs to the 18 turning machines around the plant, including the current count of five Cincoms.
Two dozen jobs have already been transferred from the multi-turret fixed-head lathes to the new sliding-head models for one-shot machining, freeing the former for other production tasks. Such versatility is ideal for an outsourcing environment, resulting in faster deliveries to customers, better reputation and more orders.
Mr Anthony also pointed out that as space in the Redruth workshop is quite limited, replacing machines with much more productive models is an ideal way to grow the business without the expense and disruption of moving to new locations. larger premises. This is particularly important for its production of turned parts, which accounts for three quarters of the throughput.
DP Engineering – a closer look
DP Engineering is a cog in the wheel of Cornwall’s £732million manufacturing industry. It was the brainchild of an avid biker, the late David Paull, who was frustrated at not being able to get engine parts for his motorcycle and decided to machine his own. In 1952 he started an engine reconditioning business, David Paull Motor Cycles, which led him into contract machining and was the precursor to today’s business.
In 2008, DP Engineering obtained AS9100 accreditation in addition to ISO 9001:2000 and established itself as a supplier to the aerospace industry. Due to business expansion, in 2014 the company purchased a purpose-built 17,000 square foot facility in Redruth, where the contractor now operates under the watchful eye of CEO Martin Legg.
Key sectors served include aerospace, defence, oil and gas, marine and renewable energy. The company is known to be a low to medium volume workshop, producing parts typically 10-50,000 pieces. Lean manufacturing principles enable cost effective production, from prototypes to batch work, and over 500 Kanban items can be produced for next day delivery.
Other capital investments made by the subcontractor over the past 12 months, in addition to the two Cincom lathes, include a Matsuura 5-axis, 10-pallet cell for automated machining of prismatic components, an Aberlink coordinate measuring machine for inspect them and a ViciVision non-contact optical measuring machine for quality control of rotating parts.
Citizen Machinery UK