Analysis and elimination of common faults in Heidelberg offset presses (Part 1)

Fault 1: The paper arrives at the front gauge, the whole machine is shut down

Analysis: This failure is mainly caused by the paper is not running well and the light hole is not adjusted well.

Cause 1: The time before the paper arrives is too early or too late.

Remedy: Jog the machine to move the paper to the front gauge, and check whether the distance between the paper and the front gauge is 4 ~ 5mm when the front gauge is positioned on the return and dropped to the lowest point. If it is less than 5mm, the paper feed is too slow; otherwise, the paper feed is too fast. The two ï¿  13mm nuts on the operation surface can be loosened and adjusted to the standard position by means of the flange.

Failure reason 2: If the paper is not in place, it may be that the light control detection head at the front regulation has acted incorrectly.

Remedy: After jogging the machine to the front gauge and swinging to the positioning position, put a square piece of paper on the front gauge and gently push it against the front gauge. The photoelectric display lamp should be on. If there is no light, it means that one side is ahead, causing the illusion of not coming. You can turn the adjustment screw clockwise until the display light is on, and then turn it into 1 or 2 circles.

Cause 3: If the two photoelectric display lamps are found to be unlit or dark when they are on, it may be due to impurities such as paper hairs on the optical eye, which may cause photoelectric detection errors.

Remedy: Wipe clean with a soft cloth dipped in alcohol.

Cause 4: The tooth opening is too small. You can jog the machine to check it. When you find that the swinging teeth swing down to snap the paper back, the paper is judged to be caused by the swinging teeth.

Removal method: Jog the machine to the position where the paper is delivered to the paper table, and then use a 90 ° right angle gauge to measure the 90 ° position of the tooth pad and the paper board. Tooth nut (operation surface), insert a 1mm screw into the tooth, and then use a 3mm hex wrench to adjust the adjusting nut, which is subject to a little resistance when pulled out.

Cause 5: Paper skew or paper burrs may cause downtime.

Remedy: At this time, the feeder and paper feed lever can be adjusted so that the speed on both sides is consistent.

Fault 2: The paper side gauge is not pulled in place

Failure reason 1: Due to the long use time of the two mobile phones, especially the abrasion of the pull rod of the body, the pull plate is pressed against the lower table and the pull ball cannot touch the pull bar.

Remedy: At this time, you can loosen the two ï¿  5mm fastening nuts on the pull rod, remove the pull rod, and use 0.1mm steel sheet (depending on the degree of wear) to make it consistent with the pull rod , And fasten it under the original brace, add a proper amount of lubricating oil to tighten it, the effect is good after use.

Failure reason 2: The ups and downs of the pull gauge board are worn seriously, causing the pull paper to not rise and fall simply, and it is also easy to cause the paper to not be in place.

Removal method: The lower gauge plate can be removed, and the thickness of the original wear backing is welded by 1mm, and it can be installed in place.

Cause 3: The pressure on the side gauge tension spring is too small.

Remedy: Tighten clockwise.

Cause 4: The eccentric adjustment of the pull gauge ball is too high.

Remedy: just turn it to the right.

Cause 5: When printing white paper, the pressure of 4 brush wheels is too heavy.

Remedy: lightly adjust or move it back to the proper position.

Fault 3: CPC shows a large amount of ink, but the actual amount of ink is relatively small

Cause 1: The ink fountain film is used for too long, and the leaked ink agglomerates under the ink fountain film, resulting in a drop in ink output.

Removal method: clean the accumulated ink on the eccentric cylinder (a total of 32), and replace the dirty sponge strip, and replace it with a new ink fountain film (the service life of the ink fountain film is 36 hours).

Failure reason 2: There is ink accumulation on the screw of the motor that controls the ink output, which makes the screw inflexible or even stuck, resulting in no ink output or uneven ink output.

Removal method: disassemble the 32 pieces of baffle under the ink fountain (note: the hollow sleeve on the tightening screw must not be lost), use the needle to remove the ink on the screw, and remove all the accumulated ink, and activate the CPC to make each motor It can flexibly hit from the lowest ink output to the highest ink output, and fill the tank with butter, it can maintain good ink output for a long time, and the effect is very good after use.

Fault 4: Ink transfer roller is not good

Failure reason 1: Due to long-term use of the ink transfer roller, the surface is aging, the ink transfer performance is reduced, and the rubber on the surface of the ink roller is cracked or crystallized and shiny.

Remedy: If surface crystallization occurs, it can be wiped repeatedly with gasoline dipped in pumice powder to improve the surface adsorption performance. The surface aging caused by cracks can only replace the ink roller of the same size.

Failure reason 2: When replacing the ink transfer roller, the size of the machine is not sufficiently understood, which is easy to cause the size of the replaced ink roller to be too large or too small. During the adjustment, if the ink fountain roller slips continuously, the rotation angle increases sharply, which is caused by the large size of the ink roller, and the ink transfer roller does not disengage from the ink fountain roller when transferring the ink to the ink cross roller.

Remedy: If you find this situation, you should stop processing decisively and replace the standard size ink roller. The diameter error of the general ink roller should be controlled within ± 0.5mm.

Trouble reason 3: Due to long-term use, the ink fountain roller vibrates greatly when transferring ink, and the improper adjustment of the ink transfer roller causes the hollow pins at both ends of the ink transfer roller to bend, resulting in the two ends of the ink roller not being concentric. Generally, when the ink transfer roller is working, one end is in good contact with the ink fountain roller, but the other end is not in contact with the ink transfer roller or the contact is insufficient. If the pressure between this end and the ink fountain roller is increased, the "slipping" phenomenon of the entire ink transfer roller will occur, resulting in increased vibration of the machine and a lot of darker ink colors, which cannot be printed at all.

Remedy: You can remove the cover on both sides, take off the backing of the two ends of the ink fountain, and take out the hollow pins (ï¿  8mm) at both ends of the ink transfer roller, and replace it with a new one.

Note: A hollow pin with a diameter of 6mm should be inserted into the new ï¿  8mm hollow pin to ensure that it will not deform for a long time.

Trouble reason 4: The fixing screw of the ink transfer valve control valve is broken, which causes no ink transfer or the abrasion of the ink transfer roller against the mountain, so that the ink transfer roller will also touch the ink fountain roller when the ink stops.

Remedy: Open the cover on the side of the machine's operation surface and check whether the air valve fixing screw is intact. If it breaks or falls off, it needs to be reinstalled; after installation, you can press the ink transfer roller switch to check whether the air valve is working properly. If it is abnormal, it should be disassembled and repaired and then installed. If the backing is worn more seriously, loosen the head screw ï¿  3mm on the backing, adjust it to a suitable position, and then tighten the head screw.

Flatware Set

Flatware Set,Flatware Set Luxury,Flatware Set with Case,Flatware Set on Sale

Yangjiang Ronghong Houseware Co.,Ltd , https://www.rhhouseware.com