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Produce high-precision micro parts on standard machines and thereby reduce energy costs.

Last year, Prontoplast Spritzguss AG put two fully electric ROBOSHOT machines from FANUC into operation in order to gradually make their production more energy efficient and to increase precision and flexibility at the same time.

The demanding customer parts from the fields of Life Science, Electrical Engineering and Apparatus Construction require machines which can be fine-tuned. Extremely rapid reaction times of the machines due to the short control cycles are important for the parts at Prontoplast. Even complex injection profiles can be realised efficiently in this way. The ROBOSHOT machines offer various benefits thanks to the numerous features and options. Together with the know-how from Prontoplast, they are well positioned among the competition and have no Far Eastern competitors to worry about.
You have to look carefully if Lukas Ruckstuhl shows a box with sample parts. Owner and Managing Director of Prontoplast Spritzguss AG, Wetzikon, and his two-man team specialise in technical precision parts made from thermoplastic synthetics.

The sample parts are impressively small: Ruckstuhl describes shot weights of more than one gram as “parts of a certain size”, often they weigh less than 0.1 gram and their speciality lies in parts with a shot weight of less and 1 g and item weights less than 0.01 g. The tolerances here are ± 0.01 mm. The company’s website confidently states: “We accept your micro challenge.” And even if there is no definition for “micro parts”, the smallest synthetic parts from Prontoplast are certainly included.

The company’s owner formulates the challenges like this: “Contact us with an impossible task.” Does he not want things to be easy? “The more complex the parts which are to be produced, the more we enjoy doing it.

Customers for the high-precision micro parts come from the fields of Life Science, Electrical Engineering and Apparatus Construction.

The lot sizes vary greatly from order to order. Sometimes there are only 100 parts a year, sometimes the number increases to 100,000 or even more than 10 million pieces. That means that the entire machine park has to stay flexible.

The latest acquisition is two ROBOSHOTs from FANUC. In autumn last year, the slogan “The Change” was used on the homepage to announce: Gradual more efficient production. Lukas Ruckstuhl points out that the savings in energy costs already played a role, but only in connection with the production costs generally. 
The two ROBOSHOT α-S15iA have not been in operation long enough to be able to really assess the effects on the power bill: “It is however a factor which we happily take away”, say the boss. “Criteria like productivity and quality tipped the scales.” The two injection moulding machines work with a clamping force of 150 kN, whereby one ROBOSHOT is equipped with a 16 screw, the other with a 14 screw. Tanja Grimm, Head of Sales ROBOSHOT for FANUC in Switzerland: “Prontoplast was the first company in Switzerland to use this small ROBOSHOT. Other companies have already registered their interest.” Besides quality and productivity, the numerous equipment options and not least the low footprint (867 x 2499 mm) are among the advantages.
And the old machines? The example of the machine taken out of service for the ROBOSHOT shows how carefully Prontoplast deals with injection moulding machines: With 46,000 operating hours, it certainly did not need to be scrapped. Ruckstuhl: “This was the machine which my father and uncle used to start their business. It will certainly perform as many operating hours again somewhere else.

The facility should be converted entirely to full electric injection moulding machines, little by little. The demanding customer parts (“for which we are known”) require machines which can be fine-tuned. Current examples for the spectrum of parts using the ROBOSHOT include camera optics for endoscopes, parts for hearing aids and components for fibre optic cables - parts which do not always fall in the “micro parts” segment, but are always extremely demanding and require precision production.

Everything the control can do

Lukas Ruckstuhl and Roman Kaufmann, who is responsible for quality management, have been in the business long enough to know that you can always implement optimally those things which are actually technically desirable. It is at exactly this point that the ROBOSHOT machines come into play and offer various benefits thanks to the numerous features and options. An example: Using the option “close later”, you can work in such a way that the mould only closes when it is almost vented. Even parts with very small noses, pins or shapes can be injected with accurate repetitions. “This is a great option. We have gotten a lot of out this”, agree the two quality-seekers. “In this way we can get the last two, three percent out of the machine.”
Ruckstuhl and Kaufmann acquired the knowledge about the control and cutting for practical work in a multi-day training course at FANUC in Biel: “The control was explained to us there over a three day period.

Tanja Grimm, FANUC: “All customers who started with a ROBOSHOT confirmed via the bank that they now achieve faster cycle times.” There is no question: These savings can differ greatly. Whereby in one process half a second adds up to a lot when there are millions of parts, in another process a few seconds more or less does not matter.

 Lukas Ruckstuhl confirms this from his perspective: “The argument for a machine like the ROBOSHOT is not about gaining two or three seconds, but rather that I can run a complex profile quickly and above all precisely.

Extremely rapid reaction times of the machines due to the short control cycles are important for the parts at Prontoplast. Even complex injection profiles can be realised efficiently in this way.

One ROBOSHOT option is particularly helpful here. The “AI Mould Protection” function offers the greatest mould protection: It measures the pressure on the mould and if there is a blockage or deviation from the tolerance, it keeps the closing unit open. Additional functions provide early warnings in case of wear on mould and ejector pins. On the one hand, this allows for short closing times, and on the other it allows for optimal tool protection. Ruckstuhl: “We always have this mould protection running as well.

Fully electric master plan

The company describes itself as “small and fine” on its website. With twelve employees, this is correct for both its size and its production.
Especially for the products: Lukas Ruckstuhl, the current owner, manages the company which was founded by his father Erwin and his uncles Beat in 1989, and trades as Prontoplast Spritzguss AG, Wetzikon. The two founders started with a single machine. Today, the machine park includes 18 injection moulding machines, two of which are the most recently acquired fully electric ROBOSHOTS from FANUC. About 40 tons of granulate are processed each year, a number that speaks for itself.

Material supply and parts logistics are simple to manage if 1,000 parts fit in a small box. Injection moulded parts are sometimes laid out in trays for transport, but are predominantly treated as bulk material. All injection moulding machines are automated with three-axle linear handling devices. Here too there is “a change”, as Lukas Ruckstuhl assures: “If we now go out to buy a 30t machine, we will consider whether we can also buy a six-axle FANUC robot for it.” In this way the options for the injection process would be expanded significantly.
The “master plan” at Prontoplast includes a fully electric machine park. “We are now ready to obtain real practical experience”, says Ruckstuhl about the next step. “Now the two ROBOSHOTs must demonstrate what they can do. At any rate we now have new opportunities which we can offer our customers.” He is not under any time pressure here - and ultimately the investments also have to refinance themselves. “At the moment we are still at the ‘Juche phase’ and sounding out all the options.

Before the corona crisis, the company boss was certain he was right about his anti-cyclical investment:  “We are well prepared for the next swing and I am certain that we have made a good investment.” He does not fear competition from the Far East. It would also not be more beneficial to produce a ROBOSHOT in Malaysia if the know-how is lacking. Almost 100 customers worldwide speak an eloquent language, even if customers in the Far East are mostly subsidiaries of Swiss companies. The proximity of competition from the Far East obviously does not harm the injection moulding specialists from Wetzikon: “With the parts that we produce, we are well positioned among the competition.”