The use of milling motors in shoe manufacturing
The manufacture of footwear goes back a long way in history: Even 40,000 years ago humans felt the need to protect their feet from adverse outdoor conditions. Several hundred centuries passed however, before the modern aesthetic footwear of the present was developed and consequently also manifold procedures for the manufacture of shoes. Whereas in the pre-industrial era shoes were crafted by shoemakers, today shoe manufacture is largely an industrial process. Nevertheless, the manual aspect of production is still a significant part of the process. The manufacture process is composed of three key sections: development and design, manufacture of shoe uppers and the actual shoe production.
Shoemaking in detail - the individual production steps
First, a sketch of the shoe is created, pattern pieces for the various upper parts are made and the shoe lasts are manufactured. The last is the interior profile to which the uppers are shaped and joined to the sole of the shoe. Next the various parts for the uppers are cut and glued or sewn together to create the shoe upper. The lower edges of the uppers are given a larger margin so that they can later be fixed to the inner sole of the shoe. Now the inner sole of the shoe, the insole, is made. It is the bottom part of the finished shoe, upon which the foot stands. The rest of the shoe is formed around the insole: the upper at the top and the outer sole underneath.
The shoe is moulded around the last. The uppers cover it and the insole is attached beneath it. There are several different procedures for joining the uppers with the shoe base: in industrial production, they are usually glued or sewn. So that both soles are fixed securely, some footwear manufacturers roughen the edges of the insole in order to achieve perfect adhesion. The rough surface must however, be identical along the entire length and be the same width all the way round - impossible to ensure and sustain long-term by hand. The system created by Vektor-Gruppe can remedy this. In close collaboration with the air motor specialists DEPRAG SCHULZ GMBH & CO. KG, a robot system has been developed using a durable DEPRAG milling motor for fast and accurate results.
The milling motor for perfect shoe soles
DEPRAG milling motors are particularly suited to the sustained, precise and consistent surface roughening of inner soles. The DEPRAG milling robot 27-030 with a grinding disc is the number one choice for connection to a robot. The long-life milling motors with top running precision have a space-saving design and are powerful in high torque ranges. They are available in the power class 400 W and with a torque range of up to max. 20,000 rpm. The combination of a flexible robot arm and permanently constant speed of the air motor ensures optimal results and increased working productivity.
The milling motors function according to a simple principle: The compressed air sets the rotors revolving in an eccentric cylinder into motion. In the rotor slits, there are vanes which are pushed outwards against the cylinder wall by the centrifugal force generated. Working chambers are created where the compressed air expands. Pressure energy changes into kinetic energy – and as a result rotation occurs.
In Russia, an innovative casual footwear manufacturer using the combination of the robot and DEPRAG milling motor is extremely impressed with the results: "In the past we always struggled with connection issues between the inner and outer soles. It can be difficult to guarantee a secure hold at every point around the sole. The milling motor with top running accuracy and robot guidance now enables perfect roughening of the surface so that shoe manufacture is continuingly optimised".
DEPRAG: Air motors for every application
Whether individual drive solutions or standard air motors, DEPRAG has the perfect solution for almost every application: For uncritical production conditions where for example, a robust cast iron housing is sufficient, the BASIC LINE air motor is recommended. This motor series provides customers with a wide spectrum of choice from which individual applications can be developed and manufactured following the modular principle. The series is available in the power classes 200 W, 400 W, 600 W, 900 W and 1.2 kW with a wide speed range. All BASIC LINE air motors are equipped with a spline shaft.
For more demanding specifications, such as use in a cleanroom in the food or pharmaceutical industries, the manufacturer offers the ADVANCED LINE product series of stainless steel motors featuring sealed, unlubricated, non-corrosive air vane motors. These sophisticated air motors are particularly space-saving and are the optimal solution for integration into handheld machines or systems. Their power range extends from 20 W to 1.2 kW, from small speeds to fast runners. The ADVANCED LINE vane motor is ATEX certified, reversible and even available with an integrated holding brake.
The manufacturer also has the high-power range covered with their versatile product line POWER LINE offering a large power spectrum from 1.6 to 18 kW. POWER LINE air motors reach high starting torques with an unrivalled low power-to-weight ratio in comparison with electric motors.
DEPRAG’s range of air motors is rounded off by their INDIVIDUAL LINE motor series. The pneumatic drives of the INDIVIDUAL LINE which are characterised by their low-cost, individual large-scale production. The standard program provides numerous options from which customised drive solutions can be developed and manufactured following the modular principle and therefore at an attractive price-to-performance ratio. The specialists at DEPRAG can realise a perfect solution for any application, whether it is a customised gear design, diverse spindle types or customer-specific attachment requests. They also have air motors on offer which are made from innovative materials such as ceramic.
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