For the pre-ferment, Bühler has developed a solution – JetMix – Better hygiene thanks to KOLLMORGEN´s stainless-steel servo motors1 AKMH Servomotor Using the AKMH stainless-steel motor from KOLLMORGEN, Bühler drives pumps, dosing units, and a centrifugal stirrer.
No hearty rye bread without sourdough. The stollen becomes deliciously soft when some of the baking ingredients are first mixed together and left to rise (thanks to the properties of yeast) before all the other ingredients are blended into the main dough. The mixture made mainly from cereal flour and bulk liquids such as water and milk is known as pre-ferment among bakers. With the JetMix, Bühler has developed a solution for the fully automated production of pre-ferment and sourdough. By using AKMH stainless steel servo motors from KOLLMORGEN, Bühler successfully combined high productivity with maximum hygiene.
Combine water and flour into a smooth and lump-free pre-ferment using dough hooks – this view is shared in domestic kitchens and among the medium-sized bakery sector. If the focus is on larger bakeries, then the JetMix is the ideal solution. The compact machine from Bühler does not combine water and flour mechanically, but through effective hydration. During this continual process, each flour particle is evenly hydrated by the finely atomized water spray. The result of this process has impressed users, mainly thanks to its high productivity and the quality of the fine and smooth pre-ferment.
The quicker way to the perfect pre-ferment
The technical aspect of the JetMix consists of four servo axes: Two of them form the pump drive for the water and ensure the pre-ferment is pushed along. Each of these axes drives the dosing screw as well as the centrifugal stirrer. “There, the flour is accelerated radially so that we can create a perfectly formed ring from flour”, describes Heinz Lauermann, team leader of Material Handling Powder & Liquids at Bühler. The ring of flour that arises from the centripetal force reacts with the water spray in the mixing tube, which is introduced from the outside through fine nozzles by the servomotor driven pumps. The pressure is accurately regulated by the precisely operated servo drive.
Bühler´s JetMix processes flour and water into a smooth pre-ferment.
This precision is therefore necessary, because when the flour and water come into contact, they coalesce into a lump-free dough. “Mechanical kneading methods for dough production are always associated with a high energy input. With the JetMix, the production of pre-ferment is significantly faster and more energy efficient”, emphasizes Lauermann. The Swiss works at Bühler´s Headquarters is in Uzwil.
The AKMH stainless-steel motors are connected by just one cable,
including recirculation to the AKD servo controller
Always enthusiastic about special ideas and alternative solutions, for Heinz Lauermann, the advancement of the JetMix, fitted with a stainless-steel servomotor from KOLLMORGEN, which was first presented at a specialist trade fair in the USA, illustrates a highlight in the industry from a hygiene perspective. The most powerful of the four AKMH stainless-steel motors drives the centrifuge that produces the ring of flour – comparable to a hand blender.
Pre-ferments are common elements of recipes in bakeries.
Sourdough from rye flour is one of the most well-known substitutes.
“The broad speed control range of the motor helped us a lot during development to identify the correct speed for different types of flour and pre-ferments”. The finely balanced interplay between the spinning speed and the water spray being introduced with a pressure of up to 16 bar ultimately guarantees the perfect mixture – and can therefore also be stored as a tried-and-tested reproducible pre-ferment recipe in the control system. “If we had small drops rather than a fine spray, we would get lumps. Drops create lumps”, says Lauermann, who explains that after being mix in the JetMix, the pre-ferment is pumped into a storage tank for further fermentation. According to Bühler, the JetMix´s performance stands at 3.0 tons per hour. “If we multiply this amount by four, then we get the quantity of finished dough”. This makes 12 tons – and they are needed. The capacity of the ovens is especially large in industrial bakeries associated with discount stores. 100 to 120 tons of flour are processed daily for bread, bread rolls, cakes, and baked goods.
One cable solution
The single cable connection technology of the servo motors provides many advantages from a hygiene point of view.
A high speed control range for production and cleaning
AKMH Hygienic Servo Motor
The stainless-steel motors from the KOLLMORGEN series AKMH can be conveniently designed for different rotational speeds due to their wide adjustment range.
Considering these quantities in a price-sensitive market with low profit margins, there is the risk that little attention will be paid to cleaning the machines. “This task reduces productivity. The longer the cleaning takes, the less the companies earn”. During the development of the JetMix, Bühler was adamant that it would be equipped for CIP i.e. that it must be attached to a central cleaning system (Clean In Place). The AKMH stainless-steel motors from KOLLMORGEN must, therefore, operate at a high rotational speed, as that is required during the production phase. “That was an important discussion in the design of the drive system, to obtain a water velocity of up to 3 m/s, so that during cleaning, leftover dough does not remain stuck on the sides”. Moreover, the drive systems must deliver such a performance that they can even push a so-called pig through the pipes. This is shaped in a figure-of-eight, nestles up to the sides and pushes the dough caught in the pipe in to the fermentation tank. Bread factories waste less food because of this and do not excessively burden the CIP system or the local sewage plant. Furthermore, bread dough does not pass well through the sewage system and quickly begins to rot.
A more hygienic stainless-steel motor with a single cable
Heinz Lauermann even describes the exterior handle of the AKMH stainless-steel motors from KOLLMORGEN as pioneering. The use of stainless-steel 1.4404 makes the AKMH series corrosion-resistant against aggressive cleaning products. The design of all the edges to have a radius of at least 3 mm and the surface finishes with a roughness of <0.8 μm prevents the accumulation of dirt. The AKMH stainless-steel motors are connected by just one cable, including recirculation to the AKD servo drives, so that the installation of Bühler´s JetMix also contributes to the hygienic aspect. On the one hand, halving the cables halves time and space during installation and, on the other hand, is also an advantage for hygiene and operational safety. Using just one cable means soling and leaks are less likely. “Integrating the recirculation system in the motor cable was worked out very well by KOLLMORGEN”, acknowledges Heinz Lauermann. He describes a hygienic motor including “very perfectly rounded motor mountings”.
The compact units of sizes two to six are also used outside of the baking industry, especially in machine areas with direct product contact and aseptic processes. The AKMH stainless steel servo motor dissipates any lost heat effectively to the outside and therefore lowers derating. As a consequence, the FDA certified series, developed according to the EHEDG guidelines, supplies higher continuous torques at lower volumes.
The Bottom Line
Bühler´s JetMix clearly demonstrates how hygiene properties and cleaning capabilities of machines in the food industry can effectively be improved when stainless-steel motors are used. It is not enough, however, to be satisfied with the material selection for the motor housings. Rather, the contour guide, connection technology and function must perfectly meet the requirements of Food Safety. “Our eyes have been opened from a hygienic perspective by AKMH”, summarized Lauermann.
KAM Switzerland, KOLLMORGEN Switzerland
NSK Molded-Oil bearings extend service life in food plant conveyor application
A vegetable processing plant in Germany is enjoying significant benefits following the adoption of Molded-Oil bearings from NSK. Principally, the move has helped the company extend the service life of bearings on a critical conveyor from two weeks, to 40, saving considerable maintenance costs and downtime in the process.
Keen to resolve the question of why its previous bearings were failing at such an unusually fast rate, and eliminate the associated cost and time issues, the company asked NSK to investigate.
During the inspection, NSK experts soon determined the cause. Due to the rigorous hygiene standards demanded by food industry regulations, the system was cleaned thoroughly on a regular basis. However, it was found that the cleaning process prompted considerable quantities of water to penetrate the bearings and, as a result, wash away the lubricating grease.
To help combat the challenges presented by the frequently required wash cycles, NSK recommended the use of its sealed Molded-Oil bearings.
A special tribology concept (tribology is the science of wear, friction and lubrication) has been implemented for Molded-Oil bearings. For instance, the bearings are equipped with NSK’s proprietary oil-impregnated material, which comprises lubricating oil and an oil-related polyolefin resin. This material releases the lubricant, which cannot be washed out due to its consistency, continuously over a long period. At the same time, the carrier material prevents water or solid impurities from penetrating the bearing.
By adopting the bearings, service life at the plant has increased from two weeks to more than nine months. This highly successful outcome once again confirmed NSK’s ‘rule of thumb’ that Molded-Oil bearings achieve at least twice the service life of conventional grease-lubricated bearings in water and dust-contaminated environments. In this particular case, service life increased by a factor of 40.
The plant is also experiencing many other benefits. For instance, the operating environment remains clean because no grease escapes and no oil needs to be refilled. Molded-Oil bearings are therefore ideally suited to food industry applications, where thorough and frequent cleaning processes are essential. The use of stainless steel for the bearing components also contributes to this suitability.
NSK supplied the bearings for the vegetable processing plant with highly effective contact seals (DDU) on both sides for even higher levels of protection. This option is available for the standard range of Molded-Oil ball bearings. Molded-Oil is also available on spherical roller bearings and tapered roller bearings.
The special features of Molded-Oil bearings and other bearing series developed by NSK for applications in food processing are described in a new brochure, which is available as an e-book at www.nsk-literature.com.
Peening extends life
Freymatic is building shot peening plants for the construction of aircraft engines – and, to do this, it’s opting for Motion Control by KOLLMORGEN to achieve high quality requirements
The shot needs to hit accurately. This is the only way for their power to be optimally deployed. This power does not do any damage. In fact, with each hit it makes the target stronger, more solid and tougher. And this is why accuracy, air speed and the right quantity with the right measurements are so crucial. Freymatic AG from Switzerland builds shot peening systems which extend the life of heavy-duty components including those in aircraft technology. To do this, the process, similar to a blacksmith’s hammer, produces precise compression stress on the surface. Motion Control by Kollmorgen ensures that sufficient shot reaches the target – the single cable connection technology saves valuable installation time.
“When we have a breakdown, we can’t just pull over.” Those in the know describe in one sentence the safety thinking in aviation. Anyone with a broken drive shaft managing to end up relatively unscathed with their vehicle in a field or ditch would have much further to fall if they were in a similar disaster while in the air. In the face of the serious consequences of technical faults in civil aviation, all parts of an aircraft are supplied with an abundance of safety margins. One way to make heavy-duty components even tougher against the prevailing powers is using shot peening. This process is used mainly in the construction of engines.
A chain mail made of tension forces
Using pressure, the drag is able to resist a potent force. Figuratively speaking, components are placed into chain mail. The links in the chain mail consist of compression stress which the shot peen with their kinetic energy during impact with the atomic lattice. Fatigue damages only become clear later on. “Fissures in the material occur where tensile stress is prevalent,” explains Martin Hunziker, CEO of Freymatic. The connection between tensile forces and the formation of fissures is particularly critical in the construction of aircraft since it is here that lightweight construction is required. Despite their size, the blades in an engine need to be very light. This is why they are made of a titanium alloy. The next generation of engines will be even lighter – amongst other things due to the use of titanium-based compounds. But in automotive construction, too, the process is an established manufacturing practice – specifically where fatigue resistance is required.
When it comes to shot peening, manufacturers often use Roxor systems by the Swiss firm Freymatic AG. To do this, the system builders from Domat-Ems in the canton of Graubünden place an industrial robot into a hermetically sealed chamber and fully automatically equip its wrist with up to six different spray nozzles via a mechanical exchange during the machining job. While the robot takes on the motion control along the components being blasted inside the soundproofed chamber, the pressure supply and dosage unit remain outside.
The shot quantities can be selected anywhere between 1 and 10, thus achieving control deviations below three percent. This precision is necessary since it is not possible to carry out inline quality monitoring for shot peening – at least not without destroying the tool. The system operator must therefore be able to rely on the adherence to process parameters – which is why, in the field of servomotor driven dosage units, maximum precision and repeat accuracy is required. This range is achieved with a speed-controlled worm gear. The conveying screw is driven by synchronous servomotors from the KOLLMORGEN AKM series which in single cable connection technology are combined with their own AKD servo inverters.
The connection between the servo regulator and the servomotor using just one cable is also an advantage for this application since the systems can be wired up more quickly while also saving space. This is because the cable typically used for feedback signals is not required.
KOLLMORGEN opts here for a slender hybrid cable for motor and feedback.
What is special about it: The single cable connection technology works even without laborious and expensive multiturn encoders. The specialists in Motion Control and servo drive technology have developed the digital resolver SFD3 for this. The interface translates the analog data of the resolver into one digital signal which it then transfers via one cable to the regulators.
Tight tolerances in the dosage
Back to the peening system by Freymatic: In terms of construction, this consists of two pressure containers which act as a sluice between the unpressurized blasting shot store and the dosage which is under high pressure. The dosage powered by the AKM servomotors in the single-cable version represents a core function of the Roxor systems and, when operational, delivers shot quantities of between 0.1 and 12 kilograms per minute with an accuracy of +/- 5 percent. In the mixing tube and up to the spray nozzle, the shot is accelerated up to the exit speed. This speed forms the two significant process parameters and is indirectly regulated via the spray pressure in a tight window of tolerance. The pressure thus lies between one and seven bar.
Accompanying the high adjustment range in the drive control designed by TBM Automation is above all the challenge of being both delicate and fast. To do this, the drive axles regulate the speed of the dosing screw via the signals from throughput sensors. “If there is too much material, the speed drops and vice versa,” explains Silvester Tribus, managing director of TBM Automation AG. The company from Widnau, south of Lake Constance, has been working closely with Freymatic for some time already as a system integrator. The specialists in Motion Control and servo drive technology belong to the group of certified system and distribution partners of KOLLMORGEN with highly specialized engineering competence.
Precision from zero speed
To ensure that the adjustment is carried out swiftly and precisely, Urs Tobler, from the TBM management team and specializing in control technology in blasting systems, has equipped the Motion Control with a few special features. “After all, we want the system to start up quickly and need a correspondingly short amount of time until the quantity and pressure have precisely engaged.” Urs Tobler looks back to make a comparison with a time when dosage drives were still driven by DC motors which were hard to regulate, especially with small quantities, and only delivered reliable values in the upper speed range. With an additional linearization of the control performance with analog values, using the KOLLMORGEN AKMmotors, it has now been possible to “be precise even from zero speed upwards.” This control quality is said to make the process reliable across the entire adjustment range. This aspect is particularly relevant for shot peening since, after peening, it is not possible to carry out a quality analysis without damaging components.
Shot firing which is too low also results in poor values, following the motto “more is more”.
To determine where the optimum value lies, system operators can only do this with “Almen strips”, thus measuring the effect of the shot impact by the distortion of a standardized surface. The Almen values determined by the distortion of a metal measurement strip then provide conclusions as to the effectiveness of the process. This must later precisely and continuously follow the previously determined key values so that the desired effects of the compression stress is set. In a further consequence, this process only functions in conjunction with regular calibration.
The complex processes in the mechanical strengthening of metal components using shot peening shows what a significant role the precise and, above all, repeat accurate servo drive technology plays. The automation conceived by TBM Automation AG for Freymatic AG is also set up in a user-friendly way for the operator and offers a cleanly structured visualization.
Atlas Servo Amplifiers can now communicate with range of controllers
INMOCO the Daventry based specialist servo company has announced its ATLAS digital amplifiers can now be used with third party microprocessors or field programmable gate arrays (FPGAs) via Serial Peripheral Interface (SPI) communications. ATLAS digital amplifiers are made by Performance Motion Devices Inc, a leading US provider of innovative, high performance integrated circuits, boards and drive-based motion control solutions to OEMs around the globe.
Originally designed to be used in conjunction with Performance Motion Devices’ Magellan motion control ICs, ATLAS digital amplifiers can now also communicate through SPI with other controllers. This significantly increases the range of applications where ATLAS amplifiers can be deployed, and includes robotics, medical devices, laboratory equipment, scientific instruments, fan and pump control, precision motion and industrial motor control.
“The new controller options combined with the ATLAS amplifiers’ high power density, digital current loop, and IoT (Internet of Things) capability results in a powerful and flexible amplifier,” says Gerard Bush of INMOCO.
ATLAS digital amplifiers are compact single-axis modules that provide high-performance torque control of DC brush, brushless DC and step motors. Featuring the highest power density in the industry, ATLAS versions are available in 75W, 250W, and 500W power configurations in two module sizes: 27 x 27 x 13mm and 39 x 39 x 15mm.
For additional flexibility, ATLAS package options can be mounted to a printed circuit board in either vertical or horizontal configurations depending on application requirements and customer preference. ATLAS amplifiers integrate a field-oriented control (FOC) digital current loop, which enables finely-tuned motor current control and lower power consumption and noise.
“The amplifiers can record IoT information such as commanded current vs. actual current, temperature, bus voltage, etc, enabling host processor access to critical motion control parameters,” explains Gerard. This enables users to monitor system performance and proactively address problems before they arise.”
The amplifiers are powered from a single supply voltage, and provide automatic protection from overcurrent, under-voltage, over-voltage, over-temperature, and short circuit faults. Other advanced ATLAS features include; programmable gain parameters and performance trace.
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