How to optimize the material utilization rate of paper bag machine? Practical tips for reducing waste of scraps

In the fierce competition of paper bag production, raw material costs often account for more than 60% of the total cost. The waste of scraps may seem small, but over time it can devour considerable profit margins. Optimizing the utilization rate of paper bag machine materials is not an optional option, but a compulsory course related to the survival of enterprises. This article will delve into the core strategies for reducing waste of scraps, helping you convert every inch of paper into value.

1、 Source control: precise matching of material selection and specifications

Balance between weight and performance: Gain a deep understanding of the actual strength requirements for different paper bag uses. Avoid redundant costs caused by excessive use of high grammage paper. For example, regular shopping bags may use 70-90gsm paper, while premium packaging bags may require 100-120gsm, and precise matching can reduce unnecessary material expenses.
Actuarial calculation of paper width: This is the key starting point for reducing scraps. Work closely with suppliers to ensure that the width of the purchased roll or flat paper can best meet the layout requirements of your commonly used paper bag sizes. Considering the slitting loss (usually 1-3mm), accurately calculate the optimal purchasing width to avoid the generation of a large number of invalid edges on excessively wide paper.
Supplier collaboration and quality control: Establish stable supplier relationships and require them to provide raw materials with uniform weight and minimal width error (such as within ± 0.5mm). The flatness and consistency of moisture content of paper have a significant impact on the smoothness and yield of subsequent processing, and source quality is the foundation for efficient utilization.
2、 Excellent equipment: maintenance, calibration, and optimization

Regular accuracy calibration and maintenance:
Paper feeding system: Ensure uniform pressure and no wear on the paper feeding rollers, and precise alignment of the paper guide components. Micro scale deviations can be amplified into significant waste in high-speed production.
Tension control: The precise tension control system (magnetic powder brake/clutch, servo control) is the core to ensure smooth paper transportation, avoid wrinkles and stretching deformation. Regularly check the status of sensors and actuators.
Cutting unit: The sharpness of the cutting tool, installation angle, and the condition of the anvil roller are crucial. Regularly sharpen/change the knife (it is recommended to establish accurate life records), check and calibrate the cutting length accuracy (using tools such as laser rangefinders).
Scientific design of die-cutting plates:
Optimization of knife line layout: Utilize professional CAD/CAM software for knife die design to maximize material utilization. Explore advanced cutting methods such as "shared cutting" and "set cutting" to reduce ineffective gaps.
Material and process of blade line: Based on the characteristics of the paper (such as whether it contains wood pulp, coating) and order quantity, choose high durability blade line (such as tungsten steel) and laser cutting/etching process to ensure smooth and durable cutting, reduce burrs and paper tearing waste caused by blunt blade.
Rounding and stress design: Rounding knives are used in key areas such as bag bottoms and hand holes to avoid paper breakage caused by stress concentration and improve yield.
3、 Process optimization: intelligent layout and parameter setting

CAD intelligent typesetting: abandoning empiricism. Utilize professional typesetting software such as ArtiosCAD, Impact, etc. for computer-aided design. The software can automatically calculate the optimal layout of different bag types and sizes on a given paper width, significantly improving material utilization. Especially for irregular bags and multi specification mixed orders, the effect is amazing.
Accurately set process parameters:
Indentation depth and pressure: Too deep can cause paper breakage or weakness, while too shallow can affect forming. Accurate adjustment is required based on the weight and stiffness of the paper. Different batches of paper may require minor adjustments.
Glue quantity control: Adopting a precise metering glue application system (such as a servo pump) to ensure uniform glue lines and moderate width. Excessive glue not only wastes glue, but may also lead to paper penetration and glue cracking; Insufficient adhesion can result in waste. Regularly clean the glue roller and nozzle.
Speed matching: Ensure coordinated speed of paper feeding, printing (if any), die-cutting, and bottom pasting stations. Excessive speed can easily cause paper breakage and inaccurate positioning; If it is too slow, it will affect efficiency. Find the optimal balance between quality and efficiency.
4、 Technology Empowerment: Automation and Real time Monitoring

Visual inspection system:
Overlay accuracy detection (printing process): Real time monitoring of multi-color printing overlay accuracy, automatic fine-tuning or alarm, to avoid large-scale waste caused by inaccurate overlay.
Defect detection (materials/finished products): Automatically identify stains, holes, wrinkles, incomplete die-cutting, glue opening, deformation and other defects in the paper itself, and promptly remove them to prevent defective products from flowing into subsequent processes and causing greater waste.
Process Monitoring and Data Acquisition (SCADA/MES):
Real time monitoring of key parameters: real-time collection and over limit alarm of key parameters such as tension, speed, temperature (during heat sealing), pressure, cutting length, etc.
Production data traceability: Accurately record the material consumption, finished product output, scrap quantity, and reasons for each order and shift. To provide data support for in-depth analysis of the root causes of waste and continuous improvement.
OEE (Overall Equipment Efficiency) analysis: By analyzing downtime, performance loss, and quality loss, identify bottleneck links that affect material utilization.
Energy and Material Monitoring System: Monitor the energy consumption of major equipment, identify abnormal energy consumption points (which may be associated with poor equipment status leading to waste). Accurately measure raw material input and finished product output, and calculate real-time material utilization rate.
5、 Personnel Management: Awareness Enhancement and Skill Training

Strengthen quality and cost awareness training: enable each operator to deeply understand the real impact of waste of scraps on costs and corporate profits. Cultivate the zero defect concept of 'getting it right the first time'.
Standardized Operating Procedures (SOPs) and Skill Enhancement: Develop clear and actionable SOPs for equipment operation, mold replacement, first article inspection, process sampling, etc. Regularly conduct skill training and assessments to enhance operators' sensitivity and adjustment ability to equipment status and process parameters. Encourage experience sharing.
Establish incentive mechanism: Establish KPI assessment and reward mechanism (such as cost saving commission) linked to material utilization rate and scrap rate, to stimulate the enthusiasm of frontline employees to actively discover and solve problems.
Establish a closed-loop system for waste analysis and improvement:
Waste classification statistics: distinguish cutting waste edges, die-cutting waste, printing waste, bottom pasting waste, etc.
Root Cause Analysis (RCA): Conduct regular in-depth analysis of major waste types (such as 5Why analysis method) to identify the root cause (equipment? Process? Materials? Operation?).
Implementation improvement and effect tracking: Develop and implement improvement measures based on root causes, continuously track improvement effects, and form a PDCA cycle.
Practical case: Old Zhang's factory's counterattack path

Old Zhang's paper bag factory was once plagued by scraps, with an average utilization rate of only 85%. Through system improvement:

Source: Re calculated and customized the optimal width roll paper with the supplier to match the weight requirements.
Equipment: Implement visual inspection system, introduce professional typesetting software, upgrade tension control system, establish strict tool maintenance and calibration plan.
Process: Fully optimize the design of die-cutting blades and promote standardized parameter settings.
Management: Establish a waste database, implement employee skill training, and provide cost saving rewards.
One year later, the material utilization rate increased to 92.5%, saving nearly 400000 yuan in raw material costs annually, and achieving centralized recycling of waste materials.
Seeking profit from waste

Optimizing the material utilization rate of paper bag machines is a systematic project that runs through the entire chain from raw material procurement, equipment maintenance, process setting, technical application to personnel management. There is no silver bullet that can be achieved overnight, only continuous improvement and scientific management. Through the solid implementation of the above five core strategies, enterprises can not only significantly reduce raw material costs and waste disposal burdens, but also improve product quality and production stability, winning solid cost advantages and environmental benefits in fierce market competition. Treating reducing waste of scraps as the core focus of daily operations is to inject a continuous stream of vitality into the company's profit pool.