Basic knowledge of polyurethane foaming in refrigerator.

1. Technological parameters of box foaming.

Raw material temperature: (25 ±5) ℃, raw material ratio: ISO/POL=1.18 ±0.03C.

Perfusion pressure: (12: 15) Mpa mold temperature: box foaming perfusion process parameter table.

Preheating oven temperature: 45 ℃ 55 ℃ mold water temperature: 42 ℃ 52 ℃.

Preheating box temperature: (40 ±5) ℃ perfusion: see process parameters table.

Perfusion flow: (750 ±5) g / s.

Ripening time: 1200-1800S, see the requirements of the box ripening time process parameters table.

2. Technological parameters of door body foaming.

Raw material temperature: (25 ±5) ℃, raw material ratio: ISO/POL=1.18 ±0.03C.

Perfusion pressure: (12: 15) Mpa mold temperature: see door body foaming and filling process parameters for details.

Baking temperature; for details, see door foaming perfusion process parameters table ripening time: ≥ 480s.

Perfusion flow: (250 ±3) g / s.

Perfusion volume: see process parameters table.

3. Process parameters of premixing station.

Cyclopentane mixing ratio: CP:B= (12.5-15): 100.

Cyclopentane pipeline pressure: (0.2 to 0.5) MPa Cp, B mixing pressure: (3.0 to 5.0) MPa.

White material density: 1.04g/cm3 black material density: 1.24g/cm3.

4. Parameters of foaming equipment.

Platform tank pressure: (0.2-0.3) MPa before perfusion, gun head high pressure circulation time: 3s.

Upper and lower limits of flow and proportional forecast alarm: 2%, upper and lower limits of shutdown alarm: ±3%.

5. Manual inspection of material parameters

6. Sample parameters of gun head.

Sample perfusion: (300 ±600) g milky white time: (12 ±2) S.

Gel time: (box 55: 65, door 48 ±3) debonding time: (80: 100) S.

Gun density: (24 ±0.5) kg/m3 cell quality: uniform, fine, no thick, long, fibrous cell.

7. Requirements for the first inspection of the foaming box.

1) the foaming box is weighed up to standard.

2) the foaming box should not be false full, the cell is uniform and fine, the cell is thick and long, and the cell is fibrous.

3) the inner tank and layer strips should not have creases that affect the appearance.

4) there can be no cavitation in the laminate.

5) there should be no chilling, cracking or oil contamination in the inner tank.

6) there should be no large area of vesicles in the inner bladder, side plate and rear plate.

7) the front roof, middle cover plate, lower horizontal bar, side plate, rear plate and inner tank must not have concave flowers, scratches, paint stripping, and gallbladder drawing.

8) there can be no obvious concavity and convexity in the rear plate and side plate.

9) there should be no bubble marks affecting the appearance and assembly of the box, and there should be no bubble plug, fracture, damage or deformation at the outlet nozzle.

10) Box sockets, power cords, copper tubes, etc., should not be broken or damaged.

11) the box body and the left and right sides of the roof plate are separated from the seam ≤ 1mm.

12) the electrical box must not be deformed, damaged or white.

13) the front roof, middle cover plate and lower cross bar cannot be inclined or stacked, the seam distance from the front roof and middle cover plate should not be more than 0.5mm, and the seam separation of the lower transverse bar should not exceed 0.8mm.

14) the front flanging unevenness of the front roof, middle cover, lower bar and side plate does not exceed 0.5mm.

15) the degree of depression of the front roof, middle cover plate and lower bar shall not exceed that of 1.2mm.

16) the drawer and shelf are qualified for trial installation, and the size of the foaming box meets the requirements.

8. The requirements for the first inspection of the foamed door:

1) the weighing of the foamed door body is qualified, and the 24-hour freezing test of the door body is qualified.

2) the foaming material is evenly distributed in the door body, and there are no false fullness and vacuoles after foaming, and the foams are uniform and fine, and there are no thick, long and fibrous cells.

3) door handle, positioning plate and panel seam ≤ 0.2mm R position seam ≤ 0.3mm.

4) Angle distance of foamed door body ≤ 0.5mm.

5) Positioning plate deformation ≤ 0.6mm, inclination ≤ 1mm.

6) door gallbladder edge and panel seam ≤ 0.5mm.

7) the unevenness of the four corners of the door body (unpopular) ≤ 0.6mm.

8) the door panel should not have concave flowers, bubble marks, tear oil, heat transfer shedding or damage, etc.

9) plastic parts should not have cracking and obvious white mouth, damage phenomenon.

10) the test door shelf is moderately loose and tight.

11) door seal slot width dimension (5.0-6... 0) mm.

12) the size of the foamed door meets the requirements.

13) drilling to observe that there are no vacuoles in the four corners of the door body.