How to choose the consumable parts and consumables of papermaking machinery?

The core of purchasing consumable parts and consumables of papermaking machinery is to determine the selection criteria first, then control the purchasing process, and finally do inventory and verification, taking into account adaptability, life, cost and supply stability, so as to avoid downtime and quality problems caused by wrong selection.

First, make clear the core principle of selection (must be observed)

Accurately match equipment and working conditions

Check the equipment model, installation size, speed, load, temperature and medium (slurry/steam/chemicals). It is forbidden to "replace special parts with general parts".

316L stainless steel, corrosion-resistant rubber and self-lubricating bearing are preferred in wet end (wire/press); The drying part is made of high temperature resistant, wear resistant and steam resistant materials.

Heavy-duty and self-aligning bearings (such as self-aligning roller bearings) must be used for high-speed and heavy-duty parts (such as press rollers and drying cylinders).

Material is the key to life.

Metal parts: 304/316 stainless steel for screen drum/grinding plate/scraper, coated with tungsten carbide and chromium oxide in high wear area.

Non-metal: polyester and nylon are selected for mesh/carpet; Fluorine rubber, silicone rubber and PTFE； for sealing; The hardness and elasticity of the adhesive layer on the roll surface are selected according to the line.

Bearing: Self-lubricating/sealed bearing for wet end; High-temperature-resistant and heavy-duty type for drying section.

Procurement strategy for distinguish consumable parts from consumable part

Consumables (net, blanket, scraper, filter element, belt): make safe stock according to monthly/quarterly consumption+replenish regularly, give priority to cost performance+stable supply.

Wearable parts (bearings, seals, roller sleeves, grinding discs): Inventory shall be set according to life cycle+failure rate, and 1-2 sets of key parts shall be prepared to avoid supply interruption.

Accident parts (large rollers, special gears): put into production and reserve, with long cycle, high value and less replacement.

Second, the main points of purchasing by parts (direct landing)

1. Slurry preparation/flow delivery system (grinding plate, screen drum, pump parts)

Grinding plate: alloy/ceramic is selected as the material, and the tooth type is selected according to the beating concentration and fiber type; Hardness HRC55+, wear resistance, qualified dynamic balance and service life ≥3 months are required.

Screen drum: 304/316 stainless steel, uniform screen seam (error ≤0.02mm), 0.12-0.15mm for household paper, corrugated paper as required; Life span ≥ 3–6 months.

Pump parts: silicon carbide/graphite opposed grinding is selected for mechanical seal; Impeller/sheath is made of wear-resistant alloy/ceramic; Bearing with seal, heavy-duty type.

2. Wire section (forming wire, suction box panel, wire guide roller)

Forming net: polyester monofilament/multifilament is selected according to vehicle speed and paper type, and the mesh number, air permeability and wear-resistant layer are matched; Life span is 3-6 months, and antistatic and easy-to-clean models are preferred.

Water suction box panel: UHMW-PE, ceramic, wear-resistant, low friction, and high adhesion to the screen surface.

Guide roller: the rubber layer is waterproof, wear-resistant and elastic, and the bearing is waterproof, sealed and self-aligning.

3. Press section (blanket, cots, scraper, vacuum box)

Press felt: choose the bottom net+wool net structure according to line pressure and vehicle speed, and the air permeability, dehydration rate and wear resistance meet the standards; The service life is 2-4 months, and the blockage and wear are detected regularly.

Rubber roller: matching working conditions of rubber coating hardness, temperature resistance and chemical resistance; High hardness and high elasticity rubber compound is selected by linear pressure; Double lip/labyrinth seal for shaft head.

Scraper/blade: made of stainless steel/cemented carbide, with sharp cutting edge and wear resistance, which is well attached to the roller surface and needs to be repaired or replaced regularly.

4. Drying department (drying net, dryer seal, bearing, steam trap)

Dry net/canvas: high temperature resistance (120℃+), wear resistance, stable size, and air permeability matching the drying curve.

Sealing of drying cylinder steam head: high temperature, steam and wear-resistant materials (such as graphite+metal ring) are selected, which ensures reliable sealing and long service life.

Bearing: self-aligning roller, heavy load, high temperature resistance, with multiple seals to prevent steam/dust intrusion.

5. Calendering/coiling (calendering roller, pneumatic tire, cutter, belt)

Calendering roller: The coating is wear-resistant and high temperature-resistant, with high surface accuracy (such as polyurethane and cemented carbide) to ensure the smoothness of the paper.

Pneumatic tyre/pneumatic seal: aging resistance, oil resistance, temperature resistance, stable pressure and no air leakage.

Knife/blade: high hardness, wear resistance, sharpness, neat trimming and long service life.

6. Common parts (bearing, seal, belt, filter element)

Bearing: select the type according to the speed, load and environment (self-aligning roller, cylindrical roller, etc.); The wet part is waterproof and sealed, and the dry part is resistant to high temperature.

Seal: The material is compatible with the medium (water-resistant/oil-resistant/chemical-resistant), with accurate size, good elasticity and no leakage.

Belt/chain: Choose the model according to power and speed, with moderate wear resistance, tension and tension.

Filter element/nozzle: accurate, corrosion-resistant, easy to clean/replace.

Third, the procurement process and supplier management (risk control)

Supplier selection

Priority is given to the original factory, authorized agent and professional paper accessories factory, with complete qualifications and industry experience.

Investigate production capacity, quality control, delivery cycle, after-sales and price, and establish a list of qualified suppliers.

Procurement and acceptance

Make clear the technical requirements, materials, dimensions, service life and warranty period (wearing parts ≥3 months, key parts ≥6 months).

Arrival acceptance: appearance, size, material certificate, dynamic balance/hardness report, and key parts are verified by samples on the computer.

Establish a purchasing ledger to record the model, supplier, price, service life and replacement records for optimizing the selection.

Inventory and cost control

Classified management by ABC: Class A (key and high value) strictly controls inventory and quality; Class b (common) safety stock; Class c (low-value and easy-to-consume) bulk purchase.

Balance procurement cost and life: low price and low quality will increase the cost of downtime and replacement, giving priority to the best cost performance.

Carry out preventive replacement, purchase in advance according to the life cycle, and avoid downtime caused by "buy again when it is broken".

IV. Verification and Optimization (Continuous Improvement)

Track the running status, service life, paper quality and energy consumption after getting on the computer, and compare the performance of different suppliers/materials.

Regularly re-check the consumption data of wearing parts, adjust the purchase quantity, inventory and selection, and form a closed loop.

Communicate with suppliers to obtain new materials and new processes to improve the life and performance of accessories.

summary

The core of purchasing: adaptation first, material-based, process control and data optimization. Firstly, the selection criteria are determined according to the equipment and working conditions, and then the key materials and parameters are grasped by parts. By standardizing procurement, acceptance, inventory and verification, less downtime, lower cost and stable production are realized.