Presswork sample comparison is the most commonly used method of presswork quality inspection. Operators must often compare presswork with sample, find the difference between the presswork and sample and rectify timely. Pay attention to the following points during presswork quality inspection.
First Item Inspection
The core of first item inspection is to proofread content of image and text and confirm ink color. Before the first item is checked with signature by related personnel, mass production of offset printer is prohibited. This is of great importance for quality control. If the error on the first item is not found, more printing errors will be caused. The following shall be well done for first item inspection.
(1)Early-stage Preparations
①Check production instruction. Production instruction specifies requirements on production technology process, standards of product quality and clients’ special requirements.
②Inspect and recheck printing plates. The quality of printing plate is directly related to the quality of presswork that meets clients’ quality requirements or not. Therefore, the content of printing plate must be same as that of clients’ sample; any error is prohibited.
③Inspect paper and ink. The requirements of different presswork on paper are different. Inspect whether paper meets clients’ requirements. Besides, the accuracy of special ink color is the key of guaranteeing the color that is same as that of sample. This shall be specially inspected for ink.
(2)Debugging
①Equipment debugging. Normal paper feed, paper advance and paper collection and stable ink-water balance is the premise of qualified presswork production. It is prohibited to check and sign the first item when equipment is being debugged and started.
②Ink color adjustment. Ink color must be adjusted for a few times to meet requirements of the color of sample. Inaccurate ink content or random ink addition for being close to the color of sample shall be avoided. Ink must be weighed anew for color adjustment. At the same time, set equipment in pre-production status to guarantee it can be put into normal production at any time.
(3)Sign the First Item
After the first item is printed by leading machine, it shall be rechecked. In case of no error, sign name and submit it to group leader and quality inspector for confirmation, hang the first item on sample table as inspection basis in normal production. After the first item is checked and signed, mass production can be permitted.
The correctness and reliability of mass production can be guaranteed by signing the first item. This guarantees to meet clients’ requirements and avoid serious quality accident and economic loss.
Casual Inspection on Presswork
In the process of mass production, operators (presswork collectors) shall inspect and check the color, content of image and text, overprint precision of presswork from time to time, taking the sample signed as inspection basis. Stop production timely once problem is found, note that on paper slip for inspection after unloading. The major function of casual inspection on presswork is to find quality problems timely, solve the problems and minimize loss.
Mass Inspection on Finished Presswork
Mass inspection on finished presswork is to remedy the unqualified presswork and minimize the hazard and influence of quality defect. Some time (about half hour) later, operators need to transfer presswork and inspect the quality. Especially inspect the parts with problems found during casual inspection, avoid leaving problems to the processing after printing. Refer to the quality standards of the factory for mass inspection; for details, take the sample signed as inspection basis.
It is strictly prohibited to mix waste products or semi-finished products with finished products during inspection. If unqualified products are found, perform Unqualified Products Control Process strictly and make record, identification and differentiation etc.
Quality Deviation Treatment System
Effective quality management system is indispensable for successful presswork quality inspection. Therefore, the company sets quality deviation treatment system. Relevant personnel shall analyze the reasons of problems and find solutions and rectification measures. “The person who treats and guards pass takes the responsibility.” In each quality month, collect all quality deviations, assess whether all rectification measures have been put into practice, especially pay attention to repetitive quality problems.
Strict presswork quality inspection is the premise and key for printing enterprise guaranteeing good presswork quality. Nowadays, the competition in presswork market is increasingly fierce. The enterprises of presswork business shall especially attach importance to quality inspection.
Post time: Feb-24-2022