Over the course of the past century, it has been a race to cut down on the cycle time, trying to produce components as fast as possible in order to obtain the highest hourly, daily or monthly production rate possible so as to be competitive on the market.

This has led companies such as PORTA SOLUTIONS to develop transfer machines that were faster and faster as well as high-performing, with innovative solutions aimed at reducing idle times.

A practical example of this race towards higher and higher productivity rates is represented by a machine produced for years. This machine was able to produce 4,500 nuts per hour, which means that it took 0.8 seconds to make one nut.

The TRANSFER machines are veritable Formula One racecars, with exceptional speed performances, designed to produce 24/7. Even if against all intuition, this scenario changed after the crisis of 2008.

The first symptoms of this change were already seen in the early 1990s, however the change was very slow, still kept under control by the large request for volumes. With the events of 2008, everything has sped up.

AFTER 2008, THE CHANGE IN PRODUCTION ACCELERATED

In fact, the harder the crisis hit, the less important the cycle time became.

There were no longer those volumes to be produced which, until that period, were just about a certainty.

Hence, the logic of producing faster and faster in order to increase volumes no longer made sense, since the volumes were falling and it was no longer necessary to increase them from year to year.

The cycle time was no longer the factor to focus on in order to maintain or gain market shares.

This fact disoriented many users of machine tools who, having been accustomed to pursue reduction in dead times, found themselves without a goal, confused by a market that was no longer interested in cycle time.

 

FROM THE CYCLE TIME…

TO FLEXIBILITY

The large volumes having just about disappeared due to the drop in demand, combined with the emergence of Asiatic countries that were starting to conquer the markets, the only hope left for our companies was to focus on flexibility.

Since there was no hope in terms of quantities, flexibility gradually started to catch on.

New forms of services started to be offered, no longer focused on the price advantage but rather on the time factor, in other words: delivering small quantities quickly.

FAST DELIVERY OF SMALL QUANTITIES TOO

The fast delivery of small quantities became the way through which some companies started to come out of the crisis, leaving behind the competitive advantage that had made them successful until that time: the cycle time!

However, this service of quickly delivering small quantities started to be a problem for production departments, as they were equipped with Formula One race cars totally unsuited to flexible production.

These very productive TRANSFER machines have a huge disadvantage: the re-tooling phase, which takes many hours or even days for reconfiguration to the next production run. Since their production rates are so high, in the case of small quantities to be produced, after just a few hours they are stopped once again for another re-tool, to the point that re-tooling activities can take 70-80% of the time compared to the actual production.

This is why at this point, the part cycle time is not the most important thing when lot quantities drop but, instead, flexible machinery is the main weapon to be unleashed on this type of a market.

Given these re-tooling difficulties, which also entail the need to hire more qualified set up people compared to the past due to more and more changes, many companies have decided to employ a battery of machining centers in order to be flexible.

It is a reasonable initial reaction, unfortunately it is not the best way to react.

Although machining centers are indeed flexible, the negative side is that they have very low productivity rates.

IF THE MACHINING CENTER IS NOT THE BEST CHOICE, WHAT ARE THE ALTERNATIVES?

As already mentioned at the beginning of this article, the market started to feel the symptoms of the crisis to come already in the early 1990s.

At that time, PORTA SOLUTIONS and some other companies developed machines based on the Transfer concept but that were more flexible thanks to the use of 6-tool turret heads.

These machines were the forerunners of a new category of equipment that positions itself between the TRANSFER machine and the MACHINING CENTER. From the 1990s up to the start of the 2000s, these machines were launched on a restricted market one again anaesthetised by the request for high volumes, rather than flexibility.

In 2005, PORTA SOLUTIONS started to produce a set of machines called MULTICENTER, after a previous experience in the field of flexible machines of the FLEXICENTER family.

The difference between the two families is that the FLEXICENTER had 8 tools per module and was in any event produced as a special machine, consequently it carried a high cost, while the new MULTICENTER was equipped with a 24-position tool change for each work module and, most importantly, it is a mass-produced machine.

Over the years, the fact that the MULTICENTER could be mass-produced has given the company a competitive advantage from a machine cost standpoint, making it the best value in its category, and has also resulted in a product with excellent reliability.

THE RIGHT MACHINE, AT THE RIGHT TIME, AT THE RIGHT PRICE!

The other crucial element that significantly helped the MULTICENTER become so successful was the 2008 crisis.

The machine, launched on the market just a few years before the crisis hit, was the right machine, at the right time, at the right price, to meet the requests for flexibility from that moment onward.

Since 2005, we have been producing the MULTICENTER in a standard way, a mass-produced machine with delivery terms of 2 to 3 months. Here is a short list of the advantages offered by the MULTICENTER:

• PRODUCE LOTS FROM 500 TO 5000 PIECES:
• RE-TOOL IN 15 MINUTES
• PROCESS 6 SIDES DURING A PRODUCTION CYCLE
• PROCESS COMPONENTS INSIDE A 250-mm CUBE
• LOWER THE STOCK ON HAND
• PURCHASE A STANDARD MACHINE
• HAVE A LOW INVESTMENT COST
• TAKE UP LESS SPACE
• USE UP TO 40% LESS ELECTRICITY
• HAVE A LOW TOOLING COST
• EASY AND USER-FRIENDLY MACHINE

With these characteristics, it is the ideal machine for the flexible production of various components with no need to use expensive and hard-to-tool TRANSFER machines and without giving in to the temptation of installing a battery of MACHINING CENTERS.

YOU WILL BE ABLE TO MEET THE MARKET REQUESTS IN A SIMPLE AND QUICK WAY, EVEN WITH SMALL TO MEDIUM LOTS.

With this machine, you will not achieve the best cycle time versus dedicated machines, but you will be able to meet the requests of the market simply and quickly, even in the case of small to medium lots.

The issue of a fast cycle time at all costs is clearly dealt with in LEAN MANUFACTURING techniques, especially when we are talking about Takt Time.

The Takt Time represents the production rate. It is the time that it takes to produce a single component or an entire product, also known as the Sales Rate.

Takt-Time= total available time-day / customer request-day

No of operators= cycle time/takt time

The Takt Time should not be confused with the Cycle Time, which is the work time needed to complete the process being analysed. Knowing both values allows us to obtain an important cell/process parameter, which is:

• Determining the Takt Time of a product is very important in terms of not giving in to the temptation of producing the piece too quickly, as this would generate bottlenecks during the previous or following phases.
• I have seen cases where part processing was exasperated through the use of expensive, tailor-made machines, which then resulted in bottlenecks during quality control or assembly.
• The Takt Time helps to accurately determine the pace to be kept during the various process crossover phases of the product being made.

A flexible machine such as the MULTICENTER can be easily adapted to the TAKT Time. For example, if the machine produces at a rate that exceeds the established TAKT Time, we could introduce de-burring operations to take advantage of the available time.

In fact, thanks to the tool changes, it is very easy to include additional tools in the cycle specifically dedicated to de-burring activities so as to eliminate machine or personnel allocated to this task.

Another option for best machine use and for achieving the established TAKT Time is to include check cycles thanks to probes assembled in the tool changes, with the retro-action possible with machine offsets for tool wear compensation.

A MACHINE THAT IS AS FLEXIBLE AS A MACHINING CENTER BUT WITH THE FAST PRODUCTION RATES OF A TRANSFER MACHINE!

The right machine is called MULTICENTER and it is based on TRANSFER technology.

In fact, the 4-station pallet rotates like a TRANSFER, consequently it is fast; but, instead of simple transfer units, 3 actual independent MACHINING CENTERS were used, with tool change and pallet rotation B axis This is to guarantee flexibility.

THE MULTICENTER ALLOWS YOU TO ADAPT TO THE TAKT TIME BY INCLUDING DE-BURRING AND CHECKING ACTIVITIES

Below is a summary of the strengths of this machine, in line with the new processing methods of LEAN MANUFACTURING:

• VERY FLEXIBLE, IT CAN BE ADAPTED TO ALL KINDS OF PIECES TO BE PROCESSED
• SUPER FAST TOOLING: PIECE CHANGE IN 15/20 MIN.
• FAST PRODUCTION: 3 SPINDLES ALWAYS IN OPERATION
• LOWER TOOL COSTS
• REDUCED W.I.P
• LOWEST INVESTMENT COST IN ITS CATEGORY

This machine was designed to specifically meet a market request that entails small-medium lots of complex pieces requiring fast delivery times.

In addition to the above, you will also gain a competitive advantage by being able to meet in RECORD time the customer’s requests, the type of requests that manufacturing companies in developing countries are unable to meet.

This is my explanation, and of course you may say that I am biased after all. In that case, continue reading and you will get to an account by a MULTICENTER user.

THE ACCOUNT…

“The pieces we usually process on the MULTICENTER are typically horizontal machining center pieces.

On a center, to offset the tool changes and to have a “decent” cycle time, we would position multiple parts per cube.

This led to repeatability problems since the pieces were formed and not cast.

Since the MULTICENTER has three machining centers, it is competitive at the cycle time level with just one or two pieces per cube, thus simplifying the pallets and, most importantly, lowering their cost.

The same problem arises to tool the machine prior to starting a production run: having to check 16 or 24 pieces per pallet tombstone resulted in long start times.

Today, we load a maximum of two pieces per pallet with the MULTICENTER, thus significantly speeding up the tooling phase.

Another advantage is the possibility of loading and unloading using a robot, something that would not be possible with a machining center unless one was willing to invest 20 or 25 times more to build the fixtures, consequently an important reduction in personnel.

The flexibility in handling the ramp-up and ramp-down of a piece is another key benefit.

Before a piece is produced at full capacity on a transfer machine, smaller lots and pre-series productions must be carried out which, on a transfer, would not be economically feasible as it is possible with the MULTICENTER; the same thing can be said for the piece that is no longer mass-produced; usually, at the end of the service life of a piece, small lots are produced to be used as “spare parts” only, using the same tools used on the transfer.”

Fabio Ghidini

Production Manager

MI.GA.L. S.R.L.

Via Angelo Gitti, 18

25060 Marcheno – Brescia – Italia

www.migal.it

THE MULTICENTER HAS THE LOWEST COST IN ITS CATEGORY!

Now it’s your turn again!

Try to answer the following three questions; take 10 minutes of your time and answer the questions: it is very important to write them down instead of just thinking them, since writing requires concentration, that concentration that we often do not have for lack of time, and that however makes us make the WRONG decisions or, even worse, not make any decision at all.

WHAT WOULD CHANGE AT YOUR COMPANY IF YOU INSTALLED A  MULTICENTER IN ORDER TO PRODUCE SMALL-MEDIUM QUANTITIES IN RECORD TIME?

…AND WHAT HAPPENS IF YOU KEEP ON USING THE SAME MACHINES YOU HAVE ALWAYS USED IN THE PAST?

WHAT WOULD BE THE RISKS FOR YOUR COMPANY IF YOU DID NOTHING AND SIMPLY POSTPONED YOUR DECISIONS?

Maurizio Porta
Expert in Flexible Production