Plywood Grading Rules :Part 15 JPIC Grading Standard and knowledge

Plywood Grading Rules :Part 15 JPIC Grading Standard and knowledge

10/18/2004
Quality BB CC Back
Item
Knot, (pin knot is excluded), bark pocket and pitch pocket. Total number of knot, .bark pocket and pitch pocket, (bark pocket and pitch pocket of 1/8 in.  or less of maximum diameter are excluded) Not Limited Not Limited Not Limited
Sound Knot 2 in. or less of maximum diameter. Do
Dead Knot 3/4 in. or less of maximum diameter. Do
Knot Hole 1/8 in. or less of maximum diameter.  But the mended one shall not exceed 1/2 in. of maximum diameter. 1/4″ or less of MAX dia.  But the mended one shall not exceed 1/2″ of maximum diameter. 1?in. or less of maximum diameter.
Bark pocket and pitch pocket 1?in. or less of maximum diameter. Not more than 3″ in maximum diameter. Not Limited
Pin Knot Not Limited Not Limited Not Limited
Discoloration Not Conspicuous Permitted Not Limited
Stain Not Conspicuous Not Conspicuous Not Conspicuous
Decay None None Very Slight
Split It shall not exceed 1/16 in. of width and length of 10 per cent of the piece length.  But the filled one shall not exceed 1/8″ of width and length of 15 percent of the piece length. It shall not exceed 1/8 in. in width and 12″ or less in length.  But filled splits of 1/4″ or less in width and length 18″ or less are permissible. It shall not exceed 1/4 in. of width and length of 25 percent of the piece length.  But the filled one shall not exceed 1/2″ of width and length of 25 percent of the piece length.
Cross Break Length shall not exceed 10 percent of the piece length. Length shall not exceed 20% of the width. Length shall not exceed 30 percent of the piece length.
Worm Hole I. 1/16″ or less of maximum diameter.  Those shall not be clustered, so remarkably.  I. 1/16″ or less of maximum dia. and not clustered.  Not Conspicuous
II. Linear worm hole shall not exceed 5/8″ of length, but shall be mended. II. Linear worm hole shall not exceed 1 inch of length and shall be mended.  Total number shall not exceed 1 per sq.ft.
Total number shall not exceed a quotient resulted from dividing the surface area in sq.ft. by 5 sq.ft.
(If the quotient has any fraction, the quotient shall read as its integer plus “1”.)
Presence of Sapwood and heartwood on the surface. Not Limited Not Limited Not Limited
Sound burl, vine streak, cross bar. Not Conspicuous Not Limited Not Limited
Rough cut Torn grain Brashness. 10 percent or less of the surface area.  Not conspicuous. 15% or less of the surface area.  Not conspicuous. Not Conspicuous
Shim Color shall be matched. Gap is not acceptable. Do Not Limited
Joint Color shall be almost matched.  Gap of joint shall not exceed 1/32″ of width and it shall be mended. Do Gap of joint shall not exceed 1/8 in. of width.
Blister None None None
Wrinkle None None Slight
Hole (Worm hole excluded) 3/8″ or less of maximum diameter.  It shall be mended. 1/2″ or less of maximum diameter.  It shall be mended. 1?or less of maximum diameter.
Finishing Almost good finish Do Not rough
Insufficient removal of tape None Not Conspicuous Slight
Perforation and other process (Applicable only to the processed plywood) Do Do Not rough
Finishing of transparent costing which does not obscure the grain or texture. Do Do
Press Mark Max 3mm x 100mm 2 per panel, it shall be mended. 1. Same direction of grain max 12.7 mm x 200mm, it shall be mended.  Permitted if not affect face quality.
2. Cross direction of grain max 6mm x 100mm.  It shall be mended.
3. Small press mark it shall be mended.
Core Overlap Slight Slight
Core Uneven Thickness None Not Conspicuous
Core Void It shall not affect the surface core void at the edge shall not exceed 3mm of width. It affect the surface slightly. core void at the edge shall not exceed 4mm of width.

Specialthanks to the original soure of :

 

1.http://boxautomation.tripod.com/jpic.htm

2.

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