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Vol. 22
January Issue
Year 2021
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Articles


in Vol. 22 - January Issue - Year 2021
Sandblasting Meets Industry 4.0



Figure 1: parameter adjustment


Figure 2: result under the microscope


Figure 3: Sandblasting in the watch industry


Figure 4: The systems are manufactured in a modular system to ensure the best possible use of space in the respective environment


Dominik Egli

Introduction

Global Blast is an innovative company whose employees have over 20 years of experience in the construction of automated sandblasting systems. In close cooperation with competent partner companies, Global Blast will now also offer manual sandblasting  systems for industry and medicine in addition to the existing automated sandblasting systems offering. 

Industry 4.0 standard in sandblasting

The process data of the sandblasting systems (e.g. blasting pressure, throughput, cycle times, temperature and humidity) are compared with the specifications during the blasting process. If these values are out of tolerance, the system automatically makes adjustments as necessary. If this is not possible, a signal will be sent to the operator and the machine will stop processing after a given number of parts. The data and any error messages (per part) are written to the RFID tag on the part carrier and sent to the customer's own control system. The system itself stores the data of the current processing operation in the internal control system. This leads to a completely transparent sandblasting process that can be monitored from the office at any time. This allows possible quality deviations to be tracked and corrected, and subsequent processes can be better planned.

Application in the medicinal area

When blasting small / smallest parts, quality and reproducibility are becoming more and more relevant. If this reproducibility is lost in the medical industry, entire series of components may have to be examined as it is unclear when the process deviated from the standard.
Global Blast responds with equipment that uses the latest technologies and is adapted to the specific requirements. The range of applications extends from artificial hip joints to dental implant screws and covers many more segments due to the customer-oriented design. With the help of various sensors, the relevant parameters are recorded and stored on the component carrier by means of RFID tags. 
The blasting pressure of each sandblasting gun is tracked and readjusted in case of a deviation. In addition, the flow of blasting media is monitored with the help of microwave sensors (Doppler effect) to detect any foreign bodies or blockages that disturb the flow of blasting medium. A blasting media preparation system ensures that only intact blasting media moves in the blasting media cycle. These innovations guarantee a perfect flow of the abrasive media even for large series, which in turn produces a uniform surface quality. 

Applications in the watch industry

To deburr extremely fine contours and blast small surfaces in the watch industry, for medium to large series, industrial robots are used, which have a repeatability of 0.03mm. With a speed of up to 2m/sec., even larger series can be processed precisely and effortlessly. For these fine machining operations, micro-jet or injector nozzles are often used. 

Systems at first hand

To meet the requirements of the industry, the systems are designed, manufactured, assembled, programmed and commissioned completely under one roof. Thus, the entire manufacturing process can be monitored and a quick response is possible in case of any changes. This is particularly important in the medical industry, where systems are required to have all parts in contact with the product to be made of FDA-compliant materials.

How it works

Part cycle: The parts are placed in a tray on a jconveyor belt. Up to ten of these trays guarantee autonomous processing for 8-16 hours (depending on the size of the part and cycle time). The kdestacking station separates a tray, which enters the system and is positioned so that the lrobot can pick up the component in a safe position. Red light sensors are used to check the presence of the component before and after processing. Once the robot has docked on the mblasting cell, it begins with the part-specific blasting program and moves the component to the specified positions exactly in front of the blasting guns. By switching the blast guns on and off between cycles, compressed air consumption is reduced to an absolute minimum. Once the surface treatment is complete, the component is cleaned with compressed air while still in the blasting cell. The robot then undocks from the blasting cell and returns the finished part to the tray. Once the entire tray has been processed, it leaves the system and stacks the tray(s) again. 

Abrasive cycle: For surface treatment, the blasting media is fed from the nblasting media bunker to the nozzles that are mounted in the mblasting cell. The used blasting media is then pre-sorted in a cyclone. Components that are too small are removed by the ofilter system, and the rest goes over the pbucket elevator to the qtreatment plant where it gets sieved. Finally, only intact blasting media is returned to the nbunker and gets reused for the process. To ensure that the level of the blasting media does not fall below the minimum level, three capacitive sensors monitor the filling level in the nblasting media bunker. If the filling falls to a critical level, the system feeds new abrasive from a rlaterally mounted bunker.
With this design, the entire mechanical system is located outside the abrasive area and is thus protected from the sandblasting media. The robot gripper, which is the only component entering the cell, is covered by a protective hood. This hood, as well as the gripper jaws themselves, are covered with a rubber sleeve that has an extremely high resistance to the abrasive.




Author: Dominik Egli
For Information: 
Global Blast
Bischofszellerstr. 77-85
9200 Gossau SG, Switzerland
Tel.  +41.71.571 33 05
E-mail: d.egli@global-blast.ch
www.global-blast.ch