There are three main types of office chair bases: nylon, aluminum and chrome. You may wonder:
- What are the differences between them?
- How to choose?
- What are their advantages and disadvantages?
In the following content, we are going to talk about these issues one by one.
Characters
Nylon Base
Aluminium Base
Chrome Base
Materials
Color
Density
Loadability
Price
1. Chair Nylon Bases
Material
Some people may be confused about the relation between plastic and nylon. They may wrongly think the nylon has become the standard and wonder why.
Actually, plastic is a generic name, while nylon is a subclass of it. Nylon is one engineering plastic, which is often used to take the place of metal. What we use for making office chair base is modified nylon with glass fibre which is of outstanding bearing and wear properties.
In order to further reduce costs, some manufacturers on the market use PP and glass fibre as raw materials, but the office chair bases made of PP are poor in the wear resistance.
The biggest problem for plastic and solution
Both Nylon and PP belong to the category of plastics. And for the plastic, its biggest problem is oxidation and ultraviolet rays.
A chair is placed indoors, though with the relatively small effect of ultraviolet rays, the oxidation problem is still inevitable.
Therefore, it is necessary to add antioxidants to the raw materials in the production. Since nylon chair base is made by injection molding, it’s very important to accurately grasp the ratio of raw materials.
In addition to adding necessary antioxidants, it is also important to note that the proportion of secondary materials cannot be excessive. Otherwise it will affect the load-bearing capacity and service life of the base.
Specification
The density of nylon material is 1.15g / m3, which is smaller than 2.7g / m3 of aluminum alloy and 7.8g / m3 of metal iron. Therefore, only when the diameter of nylon base is large enough, can it stably support the entire chair and maintain a stable balance of the chair.
The diameter of 560MM is the minimum specification we recommend. The commonly used NYLON base diameters are 600MM, 640MM, 700MM.
Although the nylon base cannot resist hard impact like the polished aluminum or chrome base, it still can stand over a pressure of 8ookg. What’ more, even with that pressure, it still can stand firmly and stably. The higher standard one can meet the BIFMA request , with a load-bearing capacity reaching up to 1136kg .
Colours
Black is the standard color for nylon bases. White and grey are popular too. But since they require more pure raw material and more steps in the production, price is higher except black.
With the hot sales of gaming chairs, a unique style has been created in the design of nylon base to complement the colorful cushions of the chair. The pictures below show some of the customized Colorful Gaming Chair Nylon Base.
Advantages of Office Chair Nylon Bases
- Economic
- Suitable for max production, belonged to injection molding industry, simple production process, about cycle time 1.5 mins per pcs, may realize full auto production for 24 hours / 7 days.
- More color options
Disadvantages of Office Chair Nylon Bases
- Less durable. Because nylon is one kind of plastic, which will always faces the problem of oxidation once open to the air. With years passing, it will become fragile.
- If it is not maintained properly after use for years, scratches will be obvious on black nylon base.
- It looks like not so high-end.
Office Chair Aluminum Base
The aluminum chair base is made of aluminium alloy. It is more durable, which makes it the first choice for office chair manufacturers.
Production
Aluminum alloys usually contain alloying elements such as copper, zinc, manganese, silicon, and magnesium, and were invented by German Alfred Wilm in the early 20th century.
The production of Aluminum Chair Bases is die casting.
The production of aluminum alloy profiles includes three processes: casting, extrusion and oxidation.
1. Casting is the First Process of Aluminum Production.
According to the specific alloy grades to be produced, the amount of addition of various alloy components is calculated. And a variety of raw materials are reasonably matched and melted in the melting furnace.
2. Extrusion: Extrude to the BASE mold.
3. Oxidation Grinding and Polishing
The smallest size is R240-R280.
But after the aluminum alloy base come out from the machine, it still needs to be polished to shining. And the majority job is still by hands in China. The scratches and rust will be cleaned during the polishing. The polishing paste is necessary to impart gloss, with which a clear, shinning coat is made up to protect the finish.
In the production process, DIE casting and Polishing may not be carried out in the same place. Some specialized polishing workshops can concentrate on polishing aluminum alloy bases from many factories. However, scratches are prone to occur during transportation. This requires careful inspection when receiving the goods.
Compared with ordinary carbon steel, aluminum alloy is lighter and more resistant to corrosion. In a clean, dry environment, a protective oxide layer will form on the surface of the aluminum alloy.
A experiment also proved that the bending strength of aluminum alloy is three times that of ordinary steel.
So aluminum alloy base is the best among these 3 types of office chair bases: nylon, aluminum and chrome.
Causes For the Cracking of Aluminum Alloy Base
But this does not mean that the aluminum alloy base will not break. The following factors are likely to cause the aluminum alloy base to crack
- Improper proportion of other metals fused in the production
- Poor control of casting temperature
- The aluminum alloy basis thin and the materials used are insufficient, which makes the product quality poor. Then, it may be bent and broken due to insufficient bearing capacity during use
Therefore, the final process of aluminum alloy base production is usually the load-bearing test to ensure its superior quality.
Advantages of Aluminium Alloy Office Chair Base
- Light
- Strong
- High class and great looking
- Good shock absorption ability
Disadvantages of Aluminium Alloy Office Chair Base
- High cost
- Easy to get scratches during the use. If you are not careful, scratches will be made of the chair bases. Moreover, the gloss will disappear after a period of time for the wear of the clear coating
Office Chair Chrome Base
Chrome-plated chair base is made of iron. Normally it is called metal base or steel base.
Raw material is iron tube or iron sheet, produced by stamping machine, then welded together and assembled with some other parts.
Chroming is actually the process of impregnating or electroplating a thin layer of chromium on the surface of the iron. The shiny finish you see on the iron chair base is what we usually call the “Chrome” finish.
Comparison with Aluminum Base: Chromium is not expensive and less resistant to corrosion and wear than aluminum base. But its surface shows a brighter luster than aluminum, almost like a mirror.
Chrome Base Selecting Tips:
When choosing Chrome chair base, we should pay attention to the thickness of the following two materials:
Iron
- In the market, the iron thickness of the chrome chair base is in this range: 0.8 / 1.0 / 1.2 / 1.5 mm.
- The different thickness will make the load-bearing capacity vary greatly. Among them, the thickness of 1.2mm or above is the most stable.
For Chromium Layer
- Since iron pipes are prone to rust when exposed to moisture in the air, the Chromium layer must be thick enough to prevent BASE from oxidizing and rusting.
- But it’s not that the thicker the better. Because a too thick layer is not only costly, but also the adhesion of the electroplated layer will be insufficient. This will cause the surface to delamination and fall off.
Advantages of Chrome-Plated Steel Office Chair Base:
- Strong
- Semi-economic
- Shining looking
Disadvantages of Chrome-plated Steel Office Chair Base:
- Easily get scratches
Application Considerations for Chair Base
As you have noticed, each kind of chair base has it own characteristics that are decided by material and production process.
Among all these elements, the cost plays the main role, as you move from nylon to chrome plating to polished aluminum, you are likely to see product prices are increasing. Although it is tempting to buy or specify these for each product, your budget may not allow it at all.
In terms of quantity, task chairs with nylon base are no doubt to be a leading position. Most of the new companies will disappear in 3 years, which is no longer than the life of the nylon material.
Polished aluminum and chrome finishes are usually used in administrative offices and board of directors. Compared with ordinary employees, their number is limited in a company.