Kitchenware product inspection

Kitchen knives are essential tools in the kitchen, used for cutting, processing and carving food. They come in a variety of types, including chef's knives, paring knives, slicing knives, serrated knives and multi-purpose knives, each designed for different purposes. High-quality knives are usually made of high-carbon stainless steel, which is sharp, durable and corrosion-resistant, and the handles are ergonomically designed to provide a comfortable grip and stable operation.

Kitchen knife classification

According to the raw materials of the blades, they are divided into: stainless steel knives, carbon steel knives, alloy steel knives, stainless steel composite steel knives, etc.

According to the type of food processed and prepared, they are divided into: cooked food knives and non-cooked food knives.

According to the type of cutting edge, they are divided into: reground cutting tools and non-reground cutting tools.

According to their functions, they are divided into: bone cutting knives, chopping knives, slicing knives, and other knives.

According to the product structure, it is divided into: welding tools and non-welding tools.

Kitchen Knife Inspection Requirements

Material requirements

Knives should be made of materials that ensure that the finished product meets all the performance requirements of this document and should not contain any components that are harmful to health or have adverse effects on any organic tissue under foreseeable conditions of use.

Appearance requirements

The surface of the tool should be smooth and free of dirt, rust, burrs and other defects. There should be no defects with a diameter of more than 0.3mm and indentations with a diameter of more than 0.8mm on the blade surface. For defects and indentations that do not exceed this limit, there should be no more than 2 in every 10cm2 area, and the distance between any indentations and defects should not be less than 20mm. Note: Indentations or concave points that are clearly indicated as appearance designs are excluded.

Except for special design requirements, the tool should be straight and symmetrical on both sides.

Component matching requirements

The tool components should be assembled firmly and safely, and the components should not be loose. Except for special design requirements, the gap between the tool components should not exceed 0.3mm.

Surface roughness requirements

The surface roughness of carbon steel tool blades is i^a<3.2pm.

Blade Angle Requirements

Except for bone-cutting knives, chopping knives and knives with special blade angle design requirements, the blade angle of slicing knives and other types of knives should not be greater than 40°.

Blade thickness requirements

The blade thickness should meet the requirements of Table 1.

Table 1 Blade thickness requirements

Blade width mm	Tool function type	Blade thickness mm
>60	Bone cutting	<1.2
	Chopping	<1.0
<60	Bone cutting, chopping	<0.6
—	Slice	<0.46
Note: This requirement does not apply to other types of tools.

Tool strength requirements

The tool should meet the following requirements after the tool strength test: a) The blade and the knife neck should not be broken or cracked; b) The connection between the handle or its parts and the knife tenon should not be loose; c) The blade should not have a permanent deformation greater than 3°.

Tool handle connection firmness requirements

After the tool handle connection firmness test, the handle components should not be loose.

Hardness requirements

Table 2 Hardness of blade

Blade material	hardness	Hardness difference
Stainless steel	>50 HRC	<3 HRC
Alloy steel
Carbon steel	>52 HRC	<3 HRC
Stainless steel composite steel	>50 HRC; >512 HV10	<3 HRC; <70 HV10
Note: Vickers hardness is used for hardness arbitration of stainless steel and composite steel tools.

Blade sharpness and durability requirements

Table 3 Blade sharpness and durability

Blade edge classification	Tool function classification	Cutting Type A media		Cutting Type B media
		Sharpness mm	Durability mm	Sharpness mm	Durability mm
Regrinding	Chopping	>25	>100	>30	>100
	Slice Class	>30	>120	>50	>150
Non-regrinding	-	>25	>1100	>50	>1500
Note: This requirement does not apply to bone-cutting knives and other types of knives.

Drop resistance requirements

The handle should not be loose or broken, and the blade should not be cracked or broken.

Requirements for environmental stress resistance of plastic knife handles

After the test, there should be no cracks on the handle.

Requirements for heat deformation resistance of non-metallic tool handles

After the test, the handle should not have obvious deformation, and the gap between the metal and non-metal parts should not exceed 0.4mm.

Hollow handle water permeability requirements

After the test, the hollow shank and its connecting parts should not leak water.

Tool inspection method

Tool inspection and testing equipment

The test equipment includes:

a) A ruler with a measuring range of 0mm to 500mm;

b) A vernier caliper with a measuring range of 0 mm to 150 mm and a graduation value of 0.02 mm;

c) One Rockwell hardness tester;

d) One corrosion resistance tester;

e) Surface roughness tester;

f) a set of weights;

g) Microscope or magnifying glass with a magnification of 4 times or more;

h) Tool sharpness and durability tester;

i) A set of feeler gauges;

j) Angle measuring instrument or image projector;

k) 300N dynamometer;

l) Torque test equipment with a maximum range of 20N•m;

m) A constant temperature hot water bath;

n) VST measuring instrument.

Test environment temperature

The test was carried out at 23°C±2°C.

Appearance inspection method

Inspection is carried out by touch, visual inspection or general measuring tools.

Component fit inspection method

Inspection is carried out by touch, visual inspection or general measuring tools.

Surface roughness test method

Test with a roughness tester.

Cutting edge angle measurement method

Measure with an angle meter or image projector.

Blade Thickness Measurement Method

Measure within the range of 25mm to 35mm from the root of the knife (for knives with a blade length less than 100mm, measure within the range of 15mm to 25mm from the root of the knife) and read the blade thickness value 1mm away from the cutting edge.

Test method for connection firmness of tool handle

The test steps for the handle connection firmness are as follows.

a) Non-delicatessen knives are immersed in water at 75°C±1°C for 30 min, and delicatessen knives are immersed in water at 100°C for 30 min.

b) Immediately fix the blade after 30 minutes, and keep a distance of 50mm±1mm between the fixture and the handle. Apply axial tension and torque to the handle respectively, and keep it for 10 seconds. The applied tension and torque values ​​should meet the requirements of Table 5.

c) Visual inspection.

Table 5 Tension and torque values

Tool mass (m) g	pull N	Torque N • m
m<40	90±1	2.3
40<m<80	180±1	4.5
80<m<150	270±1	6.78
150<m<220	360±1	9.0
m >220	450±1	11.00

Tool hardness test method

Hardness test method for stainless steel, alloy steel and carbon steel cutting tools

Use a Rockwell hardness tester to measure one point each at the front, middle and back within an area equidistant from the cutting edge of 25 mm. For blades with a width less than 60 mm, measure one point each at the front, middle and back within an area equidistant from the cutting edge of 1/3 of the blade width.

Note: For tools with blade thickness less than 1 mm, select the area that meets the thickness requirements for this test.

Hardness test method for stainless steel and composite steel cutting tools

Rockwell hardness test method

After removing the composite layer, use a Rockwell hardness tester to measure one point each at the front, middle and back of an area equidistant 25 mm from the cutting edge on the base layer; if the blade width is less than 60 mm, select one point each at the front, middle and back of an area equidistant 1/3 of the blade width from the cutting edge.

Vickers hardness test method

Cut and sample vertically at the front, middle and back positions of the blade, with a sampling depth greater than 25mm (the cut surface structure should remain unchanged after cutting). Use a Vickers hardness tester to measure the base hardness of any point on the vertical section within 25mm from the cutting edge. If the blade width is less than 60mm, use a Vickers hardness tester to measure the base hardness of any point on the vertical section within 1/3 of the blade width from the cutting edge.

Drop test method

Place the tool at a height of 1.2m and allow it to fall freely onto the concrete floor in the following specified directions. After falling five times in each direction, check by touch and visual inspection: a) The handle is vertically downward; b) The back of the knife is vertically downward; c) The blade is vertically downward; d) The other side of the knife is vertically downward.

Test method for environmental stress resistance of plastic knife handles

Immerse the installed plastic knife handle in water at 70°C±1°C for 15 minutes, and immediately transfer it to the freezer of the refrigerator and keep it at -20°C±1°C for 3 hours, which is counted as one cycle. After two cycles, place the sample in an indoor environment at a temperature not lower than 15°C to normalize, and then observe the knife handle under a magnifying glass or microscope with a magnification of 4 times or more.

Test method for heat deformation resistance of non-metallic tool handles

The test steps are as follows: a) With the handle facing downward, soak the handle and half the length of the blade in hot water for 1 hour (the water temperature for non-deli knives is 75°C±1°C, and the water temperature for deli knives is 100°C; b) Take out the knife, inspect it visually and measure it with a universal measuring tool.

Test method for water permeability of hollow handles

Immerse the handle of a hollow-shank tool in water at a temperature not lower than 95°C and observe whether the handle and its connecting parts emit gas. Stop after 10 minutes.

Requirements for inspection marks, labels and instruction manuals for cutting tools

Labeling requirements

The label should contain the following information: a) trademark; b) certificate of conformity (words) and inspector (signature or code); c) production date; d) producer’s name and address.

Instruction Manual Requirements

The instruction manual should contain the following contents: a) "Read the instruction manual carefully before use"; b) product classification; c) instructions for use and warnings related to product use; d) safety and cleaning precautions; e) implementation standard number; f) manufacturer's name, address and contact number.