YvY.4 A myblog.arts site

YvY.4
Blog Task 7

Lead author: Hanyue Hu

Glass

The structure of soda-lime-silica float glass

Glass is made by melting a mixture of minerals at very high temperature. A large amount of silica in the form of sand or pulverized sandstone is combined with soda ash and limestone to help stabilize the mixture and make the glass stronger and water-resistant. Other substances can be added during the process to alter the color, physical and chemical properties of the glass. Recycled glass (also called cullet) is added to the mixture to reduce the consumption of natural gas and resources, and improve the quality of glass by decreasing the melting temperature. The mixture is then melted in a furnace at temperatures of 1600°C.

Float glass manufacturing process

Manufacturing float glass

Melting the mixture in a furnace

Annealing lehr kiln

Glass cutter machine

Float glass manufacturing process

Float glass is widely used for making modern windows and window glass generally must be extremely flat. The process of manufacturing float glass (also known as the Pilkington process) is unique. After the mixture is melted in the furnace, the molten glass is homogenised and glass bubbles are removed. The temperature is then controlled when the molten glass is cooled to a point where its viscosity is suitable for drawing into the tin float bath. The molten glass is formed by floating it on a bed of molten metal, typically tin, and is kept at high temperature. Tin is suitable for this particular process because it is cohesive and immiscible to the molten glass. The glass flows out and flattens onto the tin surface, forming a continuous floating ribbon with extremely smooth surfaces and uniform thickness. In this process, the temperature is reduced from 1100°C to 600°C to lift the sheet from the tin onto the rollers where the thickness and width of the glass ribbon are controlled. By passing the glass sheet through an annealing lehr kiln (120m long and 6m wide machine), the glass crosses different tempered areas and it’s slowly cooled to prevent straining and cracking from the change in temperature. Finally, the glass is automatically inspected to detect flaws and it’s then cut by machines once it’s cooled.

 

Timber

Debarking in the sawmill

Debarking in the sawmill

Timber planer machine

Timber planer machine

Timber kiln - drying process

Timber kiln – drying process

 

Timber manufacturing process

Timber manufacturing process

Timber is another name for wood, a product of trees and fiberous plants. Trees are chopped down, disbranched and cut to length to form logs which are then taken to sawmill where debarking is done. Wood is used for construction purposes by sawing, cutting and pressing logs into lumber and timber, such as boards, blanks and similar materials. The head rig breaks the logs into sawn pieces with a smooth edge, and the edging process takes place where all irregular edges and defects are trimmed off to create four-sided sawnwood. The trimmer squares off ends at typical lengths before timber is separated by thickness and width. At this stage, the product is processed differently, depending on whether the final product will be produced as unseasoned or dry. Many natural features of timber only become apparent once the surface has been planed. The timber planers are used to smooth the surface of the wood, leaving a uniform width and thickness. Timbers are then left in kilns to dry using steam. At this stage, it is important to ensure optimal and consistent air circulation throughout the kiln to ensure even final moisture content can be achieved. The ending profiling process is used in timber cladding and flooring. This process provide a tongue and groove profile on the ends of each board, which makes a neat, strong end to end joint in installation. Finally, by passing the finished timber through an inline spray booth, it is given the initial protective oil application so that it has onsite protection and also reduces the step of oiling each board by hand before installation.

We can classify wood as either softwood or hardwood. Evergreen trees are often called softwoods, and hardwood is mostly from angiosperm trees. Hardwood is commonly used for construction, e.g. flooring, and softwood is used as a lower-value bulk material. In general, softwood is easier to work with and nearly 80% of the timber produced in the world is made from softwood. In new domestic housings, timber framed construction has become extremely common.  Timber framed structures were built with oak in the past, but now Douglas fir has become the most popular wood for most types of structural building. In some housing construction, timber can also be found as supporting materials especially in roofing, flooring, framing and exterior cladding.

Pitched / Flat timber roof construction

Pitched / Flat timber roof construction

Timber floor construction

Timber floor construction

Timber wall construction

Timber wall construction

References:

http://www.glasstopsdirect.com/how-glass-made.php

http://www.diffen.com/difference/Hardwood_vs_Softwood

http://www.woodformarchitectural.com.au/?page_id=1431

 

Leave a Reply

Your email address will not be published. Required fields are marked *


*

Skip to toolbar