Four types of pillow advantages and disadvantages
Good pillows help us have a good night's sleep. After a busy day, I believe that everyone does not want to sleep all night because of a pillow. It is important to buy the right pillow for you. Different types and materials of pillows have different effects on us.
Latex pillow
Ralph Rossdeutscher, a manufacturer of natural surface products, says there are two types of latex pillows: foam core and granular core. Latex is solid and has good support, but not everyone likes it. In a recent study, latex pillows were much more comfortable than polyester pillows and feather pillows, and the quality of sleep was higher. The testers complained less about neck pain.
Advantages: can be used for 15 to 20 years; good support for the head and neck; dust mites
Disadvantages: expensive; poor ventilation
Wool pillow
This natural fiber helps maintain body temperature, is stable and durable. It does not deform, agglomerate or hollow out over time and is hypoallergenic. Wool absorbs moisture from the surface, which prevents dust mites and mold, and is more than 7 times dryer than other fibers.
Advantages: Durable than polyester pillow, dust-proof, good for maintaining body temperature
Disadvantages: expensive; only support stability
Polyester pillow
Those synthetic pillows - often referred to as "fiber filling", "microfiber" or "cluster fill" - are the most common on the market. Polyester pillows need to be replaced every two to two years. If you need more support for your head and neck, you should replace it with a filler.
Advantages: cheap, machine washable
Disadvantages: easy to flatten, short use period, easy to grow aphids
Memory foam pillow
Memory foam is a heat-sensitive material – the so-called viscoelastic – that shapes our head and neck, so it is important to have a pillow in place. The memory foam developed by NASA for space capsules has soft and stable properties and can last for 15 to 20 years.
Advantages: Recommended for people with neck and back problems or family allergies and pregnant women; dust mites
Disadvantages: expensive
Plate rolling is a process of continuous three-point bending of sheet metal using a plate rolling machine. The equipment puts the sheet material between the upper and lower work rolls when rolling. The upper roller is raised and lowered vertically, and the two lower rollers rotate and move horizontally relative to the axis of the upper roller. When the upper roll descends, the plate is plastically deformed and bent between the upper and lower work rolls. The continuous rotation of the bottom roller drives the steel plate to advance and retreat through the friction between the plate and the roller to complete the coiling.
1. Pre-bending. When the plate is rolled, there is a length at both ends of the plate that does not bend because it does not touch the upper roller. It is called the remaining straight edge. In the process, the minimum force arm at which the plate starts to bend is called the theoretical remaining straight edge. The bending form (symmetrical bending, asymmetrical bending) is related.
2. Centering. The purpose of centering is to make the generatrix of the workpiece parallel to the roller axis to prevent skew.
3. Roll round. Rolling is the main process of product forming, which is divided into two types: one-time feed and multiple feeds. Multiple feeds are commonly used for rolling thick plates. The number of feeds depends on the technological constraints (such as the maximum allowable deformation during cold rolling) and equipment constraints (such as non-slip conditions and power conditions). When the rebound of the cold coil is significant, a certain amount of overcoiling must be added.
4. Straightening round. The purpose of rounding is to make the curvature of the entire circle as uniform as possible to ensure product quality. The general rounding process is divided into three steps:
(1) Load: According to experience or calculation, adjust the work roll to the position of the required maximum correction curvature.
(2) Rounding: Roll the roller 1 to 2 turns under the corrected curvature to make the entire curling rate uniform.
(3) Unloading: gradually unload the load, so that the workpiece is rolled several times under the gradually reduced correction load.
Rolling Machine,Three-Roller Bending Machine,Four-Roller Bending Machine,Roll Forming Machine
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