Today’s challenges of automotive glass manufacturers

Automotive glass manufacturers are forced to face great challenges daily. Especially now since world financial crisis had almost immediate impact on the industry. The slowing economy drives the new vehicle sales down with out exception in each continent. To Remain competitive, more than ever now all manufacturers from largest multinational corporations to smaller private companies are seeking ways to cut costs, improve efficiency and production yields – at least they should be, by now.

Ever rising energy prices are making each windscreens production cost higher and when we add on top of this all the costs arising from waste pieces, used working hours, and possibly extended development periods, the margin per piece simply comes smaller and smaller. Without continuous efforts to boost up the yield, productivity, efficiency, and quality, company will end up losing ground to its competitors. Well trained, professional and committed staff is a key factor when companies fight their way through these rough times. THE PROCESS From raw glass warehouse, to cutting table, grinding, washing, long pair powdering and short pair to printing, short pair is dried and finally glasses are paired again. After this so called “cold-end” of the process is done and the glass is half way in the process chain. It is amazing how much these processing methods still vary today. It is common to see glasses hand cut and separating powder applied manually while in the other hand larger more developed companies use completely automated production lines with robots and automatic measuring. Although these companies are set to aim different markets, both can make profitable business. With out any deeper knowledge on the cold-end part everyone can understand that a lot can be done wrong and many to cut costs and improve efficiency. Automatic quality control monitoring is available for the manufacturing lines, but due to the costs the quality is still monitored by the operators. From these processes grinding and powdering can cause breakages and defects later, in and after bending process. Therefore it is important to monitor these processes carefully. After the “cold-end” the process chain continues with bending the most demanding process of the complete chain. After bending follows pvb assembly, vacuum and autoclaving. This article will focus more on the “hot-end” part of the process chain. MANUFACTURING CHALLENGES - Bending the most important part of the process Every day larger and more complex shapes in car windscreens come more common. Although every part of the process play their important role in the final product, it is clear that bending is the most important and demanding part. Without successful bending results the complete process fails. So called cielo and panoramic type windscreens with deep cross curvatures, tight wing shapes and small installation angle, together with thin, coloured, glass pair combinations create an “equation” that needs careful and professional care while it’s been developed into production. Bending these difficult windscreens with basic gravity bending furnaces is everything else than simple. The key issue will be – How to achieve perfect optical quality. Challenge is obvious, even to meet the optical requirements of the ECE 43 regulations and it is common that the car manufacturer has its own standards. These manufacturer standards have a tendency to be far more demanding than the ECE optical regulations. Hand in hand with this optical challenge comes the complex shape. Deep cross curvatures are sometimes some what tricky to handle. The “profile” of centre section of the glass easily contains “flat” or “reverse” parts. In other words the cross curvature is not smooth and continuous, as part or parts of the windscreen is left “flat” or has “reverse bending”. These “flat and reverse” areas cause problems in “wiperbility” and in worst case these defects will cause reflections on the optical examination. Due to the challenging characteristics of the windscreen and quality requirements the bending trials can get uncomfortable while the perfect heating configurations and tooling settings are being searched for long periods of time and often without any encouraging results. After a while the work can come into a halt. Correct heating configuration and advanced tooling are highly important, but it is also necessary to realize that good optical quality cannot be reached if the process chain from cutting until final inspection is not in order. The latest model serial gravity bending furnaces are equipped with wide range of features, but still the challenge is real. The biggest advantage on new furnaces is the well improved heating element controls and endless possibilities of adjustments. In fact so many that an average shift operator does not know half of the parameters and the functions behind. Older furnaces have their limits when it comes to producing the windscreens for latest car industry innovations, and we are not talking only about the physical limitation set by the chamber size. Coloured, thin glass pair combination and a complex shape can prove out to be impossible to manufacture without up to date machinery. Unfortunately investing into a new furnace can be too expensive. Similar challenges are faced with coach, special vehicle and bus windscreen manufacturing. Biggest challenge for this segment of windscreens is the wing and corner shapes. Today most of the single chamber and serial furnaces for larger windscreens are equipped with bottom heating and position/out put power controls. These technical features enable faster and uniform heating for both short and long glass pair and a precise heating radiation control only to the areas where the radiation needs to be applied. Bottom heating further eliminates possible optical defects. Large windscreens with long and tight wing shapes together with deep cross curvature are difficult to bend to the final shape. Deformations on edge shapes and reverse bending are common problem when the glass has been forced to its shape. To achieve competitive results advanced mould tooling is very important. Advanced mould tooling allows perfect control of the windscreen from the beginning of the bending process until the very end. With different mechanical solutions the mould and glass can be controlled so that no external manipulation of the glass is necessary. Such control of the glass and mould eases reverse bendings and shape deviations on the corner areas. Generally, with both; serial and single chamber furnaces, complex bus and special vehicle windscreens are bent manually using only the basic automatic functions such as automatic heating element configuration during the bending and final bending. Other functions weight controls, slight adjustments on temperature balance and finally release to cooling (Glass Ready) are all controlled by the operator(s) during the process. Manual operating is time consuming but in some cases cannot be avoided, simply because the technology available today does not make it possible. Since the process is controlled manually it is obvious that certain level of skill is a must to successful operation. The bending is very unforgiving, and one mistake can be fatal to the end product. Well trained and committed staff is major factor in this process and the yield levels and quality can be improved to a completely new level with continuous and efficient development of the bending practises QUALITY - a true strength ECE 43 regulations determine the basic guide lines regarding the checks on conformity of production, but it leaves a lot for the manufacturer it self to decide how to measure and control the end product. When compared the manufacturers ARG windscreen manufacturing quality control measures vary widely from next to nothing to basically thorough 100 % inspections. For example: Some companies are checking all windscreens immediately after bending with the checking fixture and document the shape and size variations carefully while others still are not using no checking fixtures at all. In OEM segment the practice does not vary so widely although clear variation on quality control measures is still there. Strict quality control measures after each process are easy way to improve the yield levels and save costs when only the good parts are processed. Once again the production line staff is in a key role – they must be committed to the perfect quality idea. INDEPENDENT EXTERNAL VIEW – way to easier solutions? In every aspect of the business, companies are using consulting, coaching, training and advising when their own internal development and technical departments face a situation when there’s simply no new ideas and the work comes to stand still. Most of the times the external view is sought even before the actual stand still situation is faced. In these situations external professional view, can probably pin point the weakest spots and determine worst “reefs” to be avoided. Problems can be caused simply because the matters are looked from “too close proximity” and instead of seeing the complete picture, everyone is focused into one minor detail, “thinking inside the box”. Thinking outside of the box normally generates innovative and novel ideas. Sometimes neutral external “variable” can change a lot. Broader view, different approach, professional experience, and purely neutral opinions based only to the facts gathered, can lighten up the situation for all, in completely different perspective. Doesn’t really matter if it is a technical problem or matter of working practises – the “external variable” can be a way to easier solution. In technical problems the working pattern is very much like doctor and patient relation. The reasons are sought according to the patient’s report of the symptoms. Doctor examines the process and after analysing the observations he explains the cause and consequences and suggests possible treatments. All this is done under professional confidentiality. Since the automotive windscreens manufacturing process chain still contains a lot of “manual” and “automated manual” work it is clear that the skills and commitment of the manufacturing staff play a crucial role on the continuous development. Both multinational corporations or private companies targeting the local markets need “tools” to overcome and improve their daily practises. Efficient and necessary “tool” can be change of attitude, practical training, technical advising or possibly new machinery, but sometimes hiring help out side is necessary to define the correct solutions. article source http://www.glassonweb.com