Safety Glass Experts: elimination of process variation from gravity bending

2011-03-01 | Safety glass

Uncontrolled process variation has an effect on manufacturing processes, reducing repeatability, and causing fluctuation in quality and productivity. Additionally, uncontrolled process variation greatly increases the waste (scrap) rate. The influence of individual process variation varies from minor to significant. However, all existent variations contribute to the magnitude of effect and can create a negative synergy that potentially leads to greatly fluctuating end results and waste pieces. There are several sources of process variations within the gravity bending process, and sources must be defined, measured, analyzed, improved and controlled - ideally to the point of elimination. These actions have an essential role in improving gravity bending process repeatability and reduction of waste. This article reviews the common sources of process variations within gravity bending systems and discuss the required actions to both control and eliminate these variations.

Safety Glass Experts: elimination of process variation from gravity bending
WHAT IS PROCESS VARIATION?
Process variations are undesired changes in production processes that can affect final product quality characteristics. These effects can be seen as fluctuations in: edge size, edge shape, geometry (sagging), wing radius, optics, and residual stresses. In order to control and eliminate any process variation, all key indicators must be identified, monitored, measured and adjusted accordingly. Key process variable #1 - temperature The most important key process variable in gravity bending processes is, naturally, temperature. The glass is sagged to its final shape with heat-treatment using infrared (IR) heating elements. The windshield is annealed and cooled at a controlled rate using a combination of natural airflow and forced cooling. In the gravity bending process, temperatures are controlled by pyrometers and thermocouples. The pyrometer measures the glass surface temperature and controls automation. Thermocouples are used to control empty chamber temperatures, both as a safety function and as a process controlling device in such case where the glass surface cannot be measured due to printing, loading location or shape of the glass. Thermocouples are very precise instruments.
However, in bending furnace technology, the applications cannot be considered as reliable response variables, because they are merely an indication of ambient temperature information in individual locations of the furnace affected by various conditions making the reading at...

expand

Article taken from Glass-Technology International bi-monthly magazine (6 issues per year)
Year: 2011 number: 2
Check out Glass-Technology International magazine

1.827 Total results
Next »
Page  1 2 3 4 5 6 7 8 9 10... Last of 115 
latestOrder by:

All GlassOnline Articles

Gracogti216

2016-04-21 |  Company news
The Graco® ExactaBlend™ AGP Advanced Glazing Proportioner, a new technology specifically developed to improve real-time ...

Kibing2016gti216

2016-04-21 |  Company news
Group acquires land to build two float glass lines with plans to expand in the near future

Gerresheimergm216

2016-04-21 |  Company news
Gerresheimer’s Primary Glass Packaging plant in Chicago Heights, Illinois, is its only plant in the US manufacturing t...

MirStekla2016gti216

2016-04-21 |  Events
Mir Stekla is the biggest trade fair for the glass industry in its region - and the 2015 edition confirmed this even...

ChinaCeramicgm216

2016-04-21 |  Events
New economic report finds signs of slow growth and prescribes action to shore up losses in the export market.

AmericanCeramicgm216

2016-04-21 |  Forming
Glass makes so much of our life possible, and is also an energy-intensive industry, in need of fresh solutions to...

Landglass2016gti216

2016-04-21 |  Furnace technology
In its activities aimed at meeting market demands in architecture, furniture, household appliance, automobile and solar...

Emiratesglassgti216

2016-04-21 |  Markets & trends
Established in 1998 in Dubai, Emirates Glass is an ISO 9001 certified organization, which provides a range of high...

Glasstec2gti2167

2016-04-21 |  Product news
Is there any way to enhance the technical properties of contemporary quality insulation glass, i.e. its Ug value, light...

Spheron2016gti216

2016-04-21 |  Software
London based firm, PLP Architecture, researches the use of real world HDR data with next generation simulation software

Ocmigm216

2016-04-20 |  Company news
Responding the the many and diverse needs and demands of the stemware market, OCMI is continuing to develop and upgrade...

WiegandGlasgm216

2016-04-20 |  Company news
This article focuses on Wiegand-Glas, one of the top three glass container manufacturers in Germany. It manufactures ...

Zecchettigm216

2016-04-20 |  Company news
Some years ago, Zecchetti started to collaborate with a number of Chinese glassworks, providing them with high-tech...

THAIgm216

2016-04-20 |  Containers
This article takes us through the history of glass manufacture – in ancient and modern times – and the importance of mor...

ChinaGlass2016gti216

2016-04-20 |  Events
This year’s edition of China Glass – the 27th event – will take place in Shanghai and will, according to the organizers ...

ChinaCeramicgm216

2016-04-20 |  Markets & trends
New economic report finds signs of slow growth and prescribes action to shore up losses in the export market.

1.827 Total results
Next »
Page  1 2 3 4 5 6 7 8 9 10... Last of 115 

Our Glass Magazines & Annual Guides Read online free of charge

Glass-Technology International
 
Glass Machinery Plants & Accessories
 
World Glass Directory
 
Flat Glass World Directory
 
Return to top

Powered by GlassOnline Logo

Copyright © A151 S.r.l. 1996-2021 - All rights reserved

A151 S.r.l. - publications@glassonline.com - Cookie policy
Registered office: Via Antonio Gramsci, 57 - 20032 Cormano (MI), Italy
Company registry - Milan, REA No.: MI-2111551 | Share capital: € 10,000 | P.IVA/VAT No.: IT 02769870342