China plywood QC Inspection Experience part 10 : HOW TO INSPECT ALDER PLYWOOD GRADES and HOW TO TEST /INSPECT PLYWOOD THICKNESS

HOW TO INSPECT ALDER PLYWOOD GRADES

As I have experienced ,Alder has many different grades ,such as A-4,KAR-C,C-C,A-A,B-C,RUSTIC,A RUSTIC,KNOTTY,K-2.

Clear ine side,knotty one side,or two sides ,Repaired knots ,Sound knots …
KAR ,as I know,it is the short name of Knot Area Ratio ( KAR)  ,depending on the location of the knots, different limits apply. They are estimated in these rules by the Knot Area Ratio (KAR) which requires a grader to visualise the knots going right through the cross-section. The KAR is the percentage of the cross -section that is taken up with knots. Different limits on KAR apply for knots in the margin (outer quarter of the wide face) and for the centre (central half of the wide face).
If you can not understand their exact meaning,when you ship the alder plywood to the customer,you will be in trouble.
Plywood conditioning in plywood production and usage
When using plywood panels, one should always take into account dimensional changes caused by variations in the moisture content of the wood. Before installation or surface treatment, plywood panels should be conditioned for 3–8 days, in moisture conditions equivalent to the installation location.

The plywood panels should always be stored on a flat and even base under a roof. Stable moisture and temperature conditions are best keeping the plywood in good shape.

Whenever the strapping is removed, the pallets should not be moved using mechanical equipment as the panels, especially the overlaid panels, are slippery.

This is very important to keep good looking and useages .

COMBI CORE PLYWOOD ,ALREADY CHANGED ITS ORIGINAL MEANING

Since 2004 ,the combi core ,already changed it’s original meaning and quality .

Several years ago ,COMBI CORE ,means one layer poplar +one layer hardwood+one layer poplar …..one layer poplar +one layer hardwood+one layer poplar.Exact numbers of Poplar plies are at most  1  plyhardwood less than poplar .

Now ,changed,for example 18mm ,COMBI CORE,some plywood importers accepted 0 or  1 or 2 or 3 or 4 layers hardwood already to get COMPETITIVE PRICES .

So ,when you want to sell or buy COMBI core plywood,please explain exactly and completely ,or ,can not meet exact quality requirement .The better state the core construction in the Purchase order .

 

PLAIN SLICED RUSTIC AND KNOTTY ALDER PLYWOOD

Pricing is per sheet.
1/4″ A-2 Rustic Grade, Poplar core.
3/4″ A/B Rustic Grade,  Ply- veneer core

Our customers have plain sliced bookmatched alder and a rustic grade. I have used these and have no problem with them.

3/4″ Rustic Alder Plywood is Good 2 Sides (G2S), grade C/C, and has a 7-ply veneer core. 3/4″ knotty alder plywood is plain sliced. 48.5″ x 96.5″ sheet size.

Sold in 4 x 8 Sheets Only

RUSTIC grade is designed to provide a product where a knotty rustic look is desired for panel, cabinet and casegood construction, and moldings. Knot size and quality are limited to ensure maximized value in the re-manufacturing process. Graded from the best face, this product may have a high line Number 3 back if the defect does not structurally affect the use in re-manufacture.
knotty appearance grade where a small knot is required. It is often used for moldings, casegood construction, entry and interior doors, and furniture applications.

Our 2.0mm PLain MDF can be cut on laser cutting machine and
cut easily without leaving any flakes.Top quality bases in 2mm thick MDF as standard. Perfect for all your basing requirements.

TYPICAL APPLICATIONS

Art & sculpture, furniture and cabinet making, jewellry, models, retail display, signage, structural purposes, testing & prototyping, props & theatre.


Laser Cut Coasters in MDF
Our MDF is a very versatile and laser friendly material. Any shape can be carved out of MDF with help of Laser cutting. Even intricate designs come out well in MDF with laser cutting. Following are few coasters we have designed from 2 MM MDF.  Please contact us for more information

CERTIFICATE OF FUMIGATION

SOME SOUTH AMERICA COUNSTRIES IMPORTING PLYWOOD FROM CHINA,THEY NEED CERTIFICATE OF FUMIGATION .

ALSO AUSTRALIA MARKETS …..

PLEASE PAY ATTENTION ON THIS WHEN YOU CALCULATE THE SELLING PRICES…

Hardwood:

Beech: German, Romanian and Poland

Afromosia Wawa, Sapeli, Okume, Bosse, Mahogany, (African)

Red wood, Meranti (Malaysian)

Cherry, Walnut, Oak, Maple, Ash (North American)

Teak (Indian & Burmese)

HOW TO TEST /INSPECT PLYWOOD THICKNESS ,TWO METHODS THE PLYWOOD BUYERS SHOUD KNOW

the foreign importers always compainted that why most of the new chinese plywood exporters or manufacturers’s prices are so low than their current suppliers.they should learn something ,then they can know who are playing games .

normally new sellers sometimes play games on thickness tolearance and testing methods ,if the buyers don’t know or don’t explain how to use and where to use the plywood,maybe some problems will be created .I have met these for everyda .

Tested one crate by one crate and get an average thickness

12mm ,75 pieces per crate ,if we requested is +/-0.5mm,Minimum thickness should be 11.5mm ,Maxmimum thickness should be 12.5mm.Now,one crate total 75 pieces ,
means the whole crate Minimum thickness is 862.5mm ,MAX thickness is 937.5mm.

See the above Picture,we tested one crate thickness 884mm ,means our whole crate thickness can meet Min 862.5mm.
Then 884 divided by 75 is 11.78MM.No matter the single piece is 10mm or 13mm they don’t care .
But you know ,between the plywood there are some GAP ,so ,this is not exact thickness for each plywood.We prefer to
use SINGLE PIECE TESING AS OUR CLIENTS AND CUSTOMERS’S REQUESTED.

 

Tested the thickness one piece by one piece SINGLE PIECE

Fyi ,test every piece of the 75 pieces ,make sure every single piece ‘s minimum thickness is 11.5mm

They are acquired by cutting of hardwood plywood plates (birch, alder, beech) into long narrow battens. Base plywood is of special parallel construction with only two plies laid cross-wise. They are produced as interior with the use of urea-formaldehyde (UF) resin, for use in dry conditions (acc. to EN 636, technical class EN 636-1).Plywood Strips

Types of surface finishing:
•raw (birch, alder, beech)
•resined (birch, alder, beech)
•foil (“Elastofol”, “Finish”)
Standard sizes:
•2200/1800/1100/700x 75/70/65/50 x 25/20 mm
Thickness: 18-30 mm

Density: 680-800 kg/m3

Other sizes and thickness available on request.

Possibilities of post processing:
•machining of the edges:
◦straight (90°),
◦chamfered (e.g. 4×45°),
◦rounded
•cutting to smaller lengths.
Main areas of application: main customers for our plywood strips are manufacturers of beds. Most of contemporary beds are built with the use of plywood strips. In the furniture industry they are called bed strips or furniture strips. Other applications of plywood strips include storage furniture, banisters, decorative finishing elements etc.

Bed slats (known as furniture slats) are made from high quality hardwood, which has a special structure. Inner veneers grain run parallel to the long edge and there are two or four layers of cross-grain which are functioning as a stabilizers.

http://www.sklejkaeko.pl/

This design results in greater resistance to bending compared with the cross-glued bed slats. The inner layers have a limited number and diameter of the knots which ensures the durability of the product and also improve the appearance. Bed slats edges are milled at an angle of 45 degrees. The main application of the bed slats is the production of mattress upholstery frames. This product is made in accordance with Polish Norm and has the required certificates

By Chris Baylor, About.com Guide

PLYWOOD GRADES:

When buying plywood at your local supplier, you may notice that there are a number of different grades. The normal grading system uses the letters A, B, C & D, where A is the best quality, with virtually no blemishes and very well sanded. Grade D typically contains up to the maximum number of blemishes allowed.
The letter grades typically come in pairs, where one letter refers to the “better” side, called the face, and the other letter to the back side, opposite the face. As such, a sheet of A-C plywood will be very well finished on the face with a relatively unfinished back. Conversely, construction grade plywood would be C-D (commonly referred to as CDX plywood), which is great for structural use but not suited to be finish material.

PLYWOOD BONDING TYPES:

In addition to the plywood grades, there are four common plywood bonding types. The difference is in the glues that are used to bind the plies, or layers of the plywood.

INTERIOR PLYWOOD:

Plywoods for interior use only are made from various hardwood and softwood species, and can be used only in interior applications such as wall sheathing, furniture (where exposure to moisture is limited), cabinetry and the like. Interior plywood is available in most grades, as well as a number of hardwood species such as birch, oak and cherry.

EXTERIOR PLYWOOD:

The most common type of plywood, readily available at home centers. The glues used in exterior plywoods are much more resistant to moisture than interior plywoods. Once again, nearly all grades are available, with A-C, B-C and CDX the most common. Numerous hardwood species are also available in exterior varieties.

MARINE PLYWOOD:

When moisture resistance is a priority, look into marine plywood. This type uses the best adhesives and is manufactured to the highest standards. It also is most commonly graded as A-A, with two top grade faces, but is limited in the hardwood choices that are practical for use in marine settings.

STRUCTURAL PLYWOOD:

When the appearance of the face is of lesser concern than the strength and stability of the material, structural plywood will typically be the choice. The resins used to adhere the plies are designed for extra strength to avoid separating of the layers. Structural plywood is seldom found in a grade higher than C-D. It is commonly used in concrete forms on construction sites.

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