Tornos Multi-Spindle Machine Reduces Cycle Times

Otto Engineering has improved its output and reduced cycle times after purchasing a Tornos Multialpha 8x20 multi-spindle machine. Otto Engineering markets its products via two divisions: Otto Controls and Otto Communications. The machine shop is run by John Lang and services the controls division, which manufactures parts for an extensive line of switches and grips used in forklifts, tractors, medical defibrillator paddles, washing machines, F1 steering wheels, B2 bomber flight controls and much more.

The communications division of the Carpentersville, Illinois-based company manufactures and assembles headsets for large corporations and for pilots and military in the field. When Lang joined Otto Engineering 22 years ago, he knew that as an engineering-focused OEM, Otto had great products but the machine shop was taking too long to produce components and there was too much waste. The company needed to make parts more efficiently so it could bring prices down on end products and stay competitive.

The ISO:9001, ISO:14001 and AS9100B business added several machines over the next 15 years - including a dozen single-spindle turning centres - and began to make parts in a more modern way. Employees worked to consolidate and pre-set tools in the turning centres to reduce setup times and streamline production. When the turning centres were at full capacity, Otto realised it needed more spindles to meet demands. Instead of simply purchasing more single-spindle turning centres, the company looked at the problem from an engineering perspective and then visited the IMTS show in 2002.

The solution appeared as a multi-spindle turning centre. The team wondered if it could get the job done using less floor space and less overheads by purchasing one multi-spindle machine instead of several single spindles. Working with companies such as Nasa, Boeing, Caterpillar, John Deere, Toro and Motorola, as well as the US military, Otto sought to reduce its parts inventory to 'just-in-time' levels - from one months worth of parts to one weeks worth of parts - or less. The plan was to run 400 different part numbers on a multi-spindle with an average lot size of 100 pieces.

But as multi-spindle machines are generally classified as lower flexibility, higher-volume machine tools, the company was determined to find out if a multi-spindle machine could indeed handle its high flexibility, low-volume workload. A multi-spindle machine turned out to be the solution and the company's cycle times reduced from one minute to 10 seconds; it made Otto so productive that within just four years it was at capacity again. It was soon realised that Otto didn't have the capacity it desired and the machine was not particularly well serviced - leaving the company wide open to lengthy and unacceptable downtime.

'We were doing a fine job making parts on the multi, but I didn't like the machine, so I started looking around for another,' said Lang. 'When Hydromat highlighted Tornos, I was immediately interested,' he added. In January 2008, Otto took delivery of a Tornos Multialpha 8x20. 'The Tornos has eight spindles instead of six, so I can put more tools in the machine and get more families of parts,' said Lang. 'Instead of taking something out and putting something in, it's already there and ready to go. 'There were parts that we have on [the Tornos] that for instance we would have liked to put in the other multi, but we couldn't because there were too many features, grooves, threads and double threads, and as the machine goes around, you run out of stations.

'With eight spindles you can add a groover and an extra threading operation or another slot and so on,' he added. Cycle times have also been reduced using the Tornos. One particular part that took four minutes on the other multi takes 20 seconds on the Tornos. And the parts come off 100 per cent complete. While Lang recognises that the team is not using the multi-spindle the traditional way, the system the company has developed works well. Otto's controls division has 15 major product categories with thousands of individual products under each category. It has 30 full-time engineers constantly working on new products. This means the Tornos multi-spindle has to be very flexible.

'Normally when a person buys a multi-spindle, they buy it for making one part and a million of them,' said Lang. 'But we will set the Tornos up for 30 pieces. 'We'll also set it up for 1,000 pieces or even 15, 50 or 3,500 pieces,' he added. No matter what size part the company is making, it always uses 7/8in diameter aluminum to do it. 'If we're making a 1/2in diameter case, we make it out of 7/8in diameter,' explains Lang. 'The material is there and never changes. 'After the first program is complete, our setups are scheduled for 15 minutes or less. 'Most people associate a multi-spindle with a three-day set-up.

'We've reduced our setup times through engineering and pre-set tooling,' he added. As an example, one part the company is producing will become a sealed 'trim' switch about 1.25in long, with a milled slot in one end and three milled notches in the other. There is a deep O-ring sealing surface on the inside and a pinhole on the outside. 'If we set up a part such as this in one of the other machines, it would cost too much and could take hours,' said Lang. 'Now, we just push a few buttons and off we go,' he added. The company uses pre-set tooling and a single material protocol to save on setup time and the wasted material only costs an average of one dime per part.

'We actually make more money in the lower volume stuff,' explains Lang. 'Someone even orders 15 pieces - there's not another switch company out there that would set this up for 15 pieces. 'We do it and make money on it because we can charge more for the switch. 'I don't think a lot of people would think to give away the six cents of material difference between the small button parts and the big parts. 'Because I get money back on the chips, six cents really might be four cents. 'Plus, if you consider the changeovers - to changeover that bar feeder and all eight collets, pickoff, get it running, knock out the little bugs in it, it's a day of production,' he added.

Another idea from Otto is a parts-collection system that was created to help run lights out. The system has four baskets, each perched over a stainless drawer that rests on a rolling platform. The whole thing is about 6ft long by 2ft high by 2ft deep and rolls into position on large casters to sit under the parts conveyor catching finished parts as they fall out of the machine. It separates parts by part program or by hour and helps with quality control - allowing Otto to back track to a particular bin when a problem occurs. 'Our goal is to have 50-75 parts or work orders through this [Tornos] machine every single month and 500 hours of production,' said Lang.

'At the end of the year, that's 6,000 hours of production. 'Eventually, we're going to have four identical bins on the other side of the machine, so on a weekend we can set the Tornos up for eight programs. 'We can have it run a certain amount of parts in each basket and it will automatically go from job to job without anybody being there. 'When I get the Tornos up to 300 programs - then I will have the flexibility to go through the families of parts and link them together - by processes and by tools. 'If we had the work, I could put one person on my two multi-spindle machines on days and one on nights; those two people would out produce the rest of the machines in the shop by 2:1,' he added.