FEATURE LINEAR MOTION
Setting glass
processing in motion
D
uring glass processing, glass edge grinding, where the sharp edges
of cut raw glass are finished for safe handling and to reduce chipping defects that can lead to breakages, is a common process. The most important and economical glass edge finish is seaming or arrissing, where the sharp edges of glass are chamfered on all four edges, top and bottom. When creating Tempered Safety Glass, this is important to contain stress, like a frame, within the glass area while it is heated to over 800˚C and then chilled. Without it, the glass would simply explode during the chilling stage. When seaming expert Ashton
Industrial designed its fully automatic seaming line, SEAMMAXX-PRO, a system of using vacuum on moving transport belts to hold each glass firmly from the underside during seaming, without any contact to the upper glass surface (which can carry a delicate, coated, heat reflecting film) was needed.
When building its automatic glass seaming line, Ashton
Industrial needed linear guides that would not only enable it to produce machines in different sizes and layouts, but that would be capable of withstanding the abrasive environment and high production rates faced by the glass processing industry. The company therefore turned to HepcoMotion for the solution
and debris sticking to the grease on the guide. Cap seals with felt wipers are used which provide effective sealing and protection, plus wiping of debris from the guide profile.
Working with water and glass dust residue can be challenging for linear equipment, as the two can result in an abrasive mix. Hepco’s V guide system effectively addresses the problem of debris entering the sliding mechanisms thanks to its self-cleaning action
and find the parallel glass edge. This allows two edges to be ground at the same time, which in turn reduces the machine size envelope and cycle times. As the heads have a mass of over 500kg, and are moving at up to 60m/min, heavy duty linear guides were essential. A pair of HepcoMotion’s HDS2 heavy
duty linear guides are therefore utilised on each pair of heads. One guide in each pair is rack and pinion driven to drive the moving seaming head back and forth.
HDS2 HEAVY DUTY GUIDES As they are below the production line in a wet environment, the HDS2 guides are coated with thin dense chrome (TDC) – a corrosion resistant coating. Stainless steel bearings are also used. The pinion is made from high grade case hardened steel for maximum wear resistance, making them a good option for working in a contaminated environment. Working with water and glass dust
LINEAR TECHNOLOGY The compact vertical machine is capable of producing cut to size lites (glass sheets) in 8-12 seconds depending on size. Fully automatic, the lites are in random mixed sequences, with sizes ranging from 150 x 300mm to 6m x 2.8m. To accommodate the vacuum belt
arrangement and keep the glass processing level clear of obstructions, the four grinding heads are mounted on tracks below the production line. There are two pairs of seaming heads, each with one fixed head and the other moving automatically in and out to seek
14 SEPTEMBER 2018 | DESIGN SOLUTIONS
SEAMMAXX-PRO is capable of producing cut to size lites (glass sheets) in 8-12 seconds depending on size
residue can be challenging for linear equipment, as the two can result in an abrasive mix. Hepco’s V guide system effectively addresses the problem of debris entering the sliding mechanisms thanks to its self-cleaning action. V guide functions on the basis of tight geometrical control over matching guide and bearing V’s. In turn this provides a wiping action that expels debris, keeping machines running and reliable. This self-cleaning action eliminates contamination of the guide. With V technology, as only a small
amount of lubrication is required to prevent wear of the guide (in some instances it can also run dry), this was beneficial for Ashton to avoid glass dust
THE RIGHT SOLUTION The heavy duty seaming heads are mounted to the HDS2 guides on a low level framework parallel to the ground, so compliance is a key requirement. The guides need to perform on an un- machined surface and so must be tolerant of a degree of misalignment. The design of Hepco’s V bearing allows for the bearing to perform on uneven surfaces and cope with variances in the mounting surfaces. Similarly, the V bearing is highly tolerant of misalignment when setting up two rail systems in parallel. Parallelism of ±0.05mm allows Ashton to reduce the set-up time needed to accurately assemble the system. In this application, blind hole V bearings are used as access to the back of the fixing plate is not possible. As the seaming heads are moved
backwards and forwards at high speed up to six times a minute to adjust to random widths of glass, smooth and repeatable movement is paramount. HDS2 provides a low friction and highly accurate system ideally suited to providing smooth indexing. Available in modular lengths, Hepco’s
HDS2 guides provided a good solution for the SEAMMAXX-PRO line, which is built in different sizes and layouts to meet customer needs. The guides are accurately machined and ended to make up butted sets. Richard Green, senior manager –
business development, Ashton Industrial, commented: “Having worked with HepcoMotion for many years, we knew their solution would provide the required precision and be able to cope in such an aggressive and abrasive environment. These SEAMMAXX-PRO lines often run 24/7 and downtime outside of planned maintenance is critical. We always found the technical support from HepcoMotion valuable and this was particularly useful when specifying for this new machine.”
HepcoMotion T: 01884 257000
www.HepcoMotion.com
/ DESIGNSOLUTIONS
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