SICURLITE. Polycarbonatglas. weit mehr als PANZERGLAS. SICURTEC Laminatglastechnik GmbH. Büro: A-5310 Mondsee, Freinbergstr. 2

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Annabelle Parsons
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1 SICURLITE Polycarbonatglas weit mehr als PANZERGLAS SICURTEC Laminatglastechnik GmbH Büro: A-5310 Mondsee, Freinbergstr. 2 Produktion: A-3362 Amstetten-Mauer, Dieselstr. 4 Telefon Fax office@ www. 1

2 Sicurtec - protective windows with Polycarbonate for machine tools acc. to DIN EN /

3 Danger from Ejected Parts in Lathe Operations Transfered Energy Extension Piece Chuck Jaw Work Piece Chuck Size 3

4 Primary Danger Zones in Lathes and Machining Centres Area of optimal Viewing Area of maximum danger from Ejected Parts 4

5 Impact Test according to DIN EN Projectile Mass Diameter Surface area Valid Range: Ejected Chuck Jaws Chuck Diameter up to 500 mm 5

6 Resistance Classification according to DIN EN Resistance Classification Chuck Diameter mm Speed of Rotation m/s Projectile Size D x a Mass of Projectile Impact Speed Impact Energy mm x mm kg m/s J over up to 6

7 Impact Test according to DIN EN Mass of Projectile m Pr = 100g Material Thickness in mm 2 Velocity in m/s Energy in Nm Worst case senario St 12.O Polycarbonate highest cutting speed m/s largest tooling diameter m highest spindle speed t

8 Ageing of Polycarbonate (PC) when exposed to coolants, lubricants or other aggressive products: Polycarbonate (PC) inspection panes are used in machine tools as elements of separation and protection. Within this application, they may fulfil different functions, viz. to keep operating personnel from accessing hazardous zones (separating function) and to protect operating personnel against ejected parts (retaining function). Consequently, the retention capacity of polycarbonate panes is of critical importance from the point of view of safety. Within the scope of a joint research project by VDW, BIA and the IWF of the Technical University of Berlin, the construction of separating protective devices was the object of in-depth analysis. The aim was to establish the state of the art concerning the retention capacity of different materials and the design of separating protective devices in machine tools. The research has shown, among other things, that long-term exposure of PC panes to cooling lubricants may lead to ageing, i.e. a deterioration of the mechanical properties (stress cracking, embrittlement). Also on the operator side the action of coolant vapours, detergents, greases and oils or other aggressive products may cause an ageing of the PC panes. The result will be a diminished retaining capacity of the polycarbonate. This must be taken into account of safety levels are to be maintained. The extent of the embrittlement of the polycarbonate was determined by impact tests (bullet tests). A summary of all available results from bullet tests performed on aged PC-panes can be found in the diagram below. Note that the following cases can be compared: 8

9 Protected polycarbonate (WITHOUT effect of cooling lubricants or other aggressive products, edge seals on all sides); Unprotected polycarbonate (WITH effect of cooling lubricants or other aggressive products, even if the influence is only partial). Alterung Ageing von of Polycarbonat polycarbonate - Sichtscheiben inspection windows Werkzeugmaschinen machine tools 120 Rückhaltefähigkeit Retention capacity (%) WITHOUT OHNE Einw effect irkung by von cooling Kühlschmierstoffen lubr. MIT WITHEinw effect irkung of cooling von Kühlschmierstoffen lubr Alter Age (Jahre) (years) Source: Quelle: BIA 9

10 The results yielded by PC panes subject to natural ageing (i.e. panes from the workshop) illustrate a distinct reduction of the retaining capacity as soon as the panes are in contact with cooling lubricants or other aggressive products. On the other hand, they show a long-term durability of up to 12 years, if the polycarbonate is effectively protected on all sides against detrimental influences. Given this ageing phenomenon, PC panes have to be classified as wear parts. Consequences for the utilization of PC panes: The embrittlement of PC panes cannot be identified by visual inspection. For this reason, it is necessary for the machine manufacturer to lay down a deadline for the replacement of PC panes having a safety-relevant retaining function. Such deadline should be based on the information furnished in the above diagram, taking into account the design principle, the dimensioning of the panes and the risk potential of flying parts. In addition, PC panes having a safety-relevant retention function against flying parts must be subjected to a visual inspection at regular intervals in order to ensure the operating safety of the machine tool. 10

11 In the following cases the immediate replacement is urgently recommended: 1. Plastic deformations (bulging) caused by impact and existing cracks; 2. damage to the edge seals; 3. coolant lubricant penetrated between the various layers; 4. destruction of, or damage to either side of the protective pane (including damage to the scratch-resistant chip-protection sheet). Recommendation for replacement of panes: The various constructions of Sicurtec safety windows, as previously described, are designed to protect the polycarbonate from premature ageing. However, in acceptance to the suggestions of the German Employers Association BIA, the Machine Tool Association VDW and the Institute for Machine Tools and Factory Operation IWF, we, as a manufacturer of machine tool protection panes, also recommend to replace the same after 5 years. Purchasers of machine tools, both new and second-hand, have to be warned explicitly of the problem of polycarbonate ageing, for instance in the Operating Instructions. We recommend printing the date of installation of the PC pane on the window itself. For replacement and maintenance of the inspection panes, the manufacturer s instructions for installation, assembly and care shall be followed. 11

Forms of Construction for Sicurtec - protective windows Sealing Spacer Edge Seal Double Seal Tempered glass Polycarbonate (hardcoated or protective film, 175µ ) Impact Side PUR-adhesive Air gap (3 or

12 Forms of Construction for Sicurtec - protective windows Sealing Spacer Edge Seal Double Seal Tempered glass Polycarbonate (hardcoated or protective film, 175µ ) Impact Side PUR-adhesive Air gap (3 or 6 mm) PUR clear glass Assymetric Glass Polyurethane PC stress free, completely flat, clear glass Assymetric Glass Air PC Symetric Glass PUR PC PUR - glass Laminated with liquid Polyurethane adhesive All Systems optional with stepped edges, splinterproof film or special coated PC and stainless steel endframes, also 282mm with holes for Rotoclear or mechanical finxing of Visiport 12

13 Sicurtec protective windows and competitive advantages A range of solutions are possible through our flexible production system Glass-Air-Polycarbonate. Distance spacer with dehumidifier Glass-Polyurethane-Polycarbonate. Completely flat, stress free, clear glass Symmetrical and non symmetrical solutions Protective units with or without stainless steel frames Furthermore Products prepared for high speed rotation windows (Rotoclear, Visiport) Special coated polycarbonates or 175µ PET-film bonded to polycarbonate on operator side From 2mm chemical toughened up to 10mm tempered glass on machine side Totally sealed stainless steel frame if required (2-part frame also spot welded Full edge sealing of window ensures highest possible protection from lubricants and chemical attacks Use of sealants which do not degrade polycarbonate through stretch factures Ongoing development and testing in collaboration with Fraunhofer Institute (IWF) at the Technical University in Berlin Individual solutions for customer requirements 13

14 Some drawings of frames and Glass/PC compositions 14

15 Sicurtec Solutions 15

16 Sicurtec Solutions 16

17 SicurTec-Protective windows for machine tools bullet-proof-tests at the Fraunhofer Institute (IWF) in Berlin A1-C3 acc. to DIN EN (Lathes) as well as DIN EN12417 (High speed machining centres) 17

18 References 18

Technical Information

Replaces technical information dated 04.05.06 Update: 10.05.06 Acrylate and dispersion based screenable pressure sensitive adhesive KIWOPRINT D 159 is a high quality, screenable pressure sensitive adhesive