What spare parts are needed for DC motor motor automatic worm gear assembly machine and how to set up guarantee stock?
I. Spare parts list
1、Mechanical parts
Transmission parts
Belt and chain: According to the transmission mode of the machine, reserve appropriate amount of spare belt and chain. If the machine uses synchronous belt drive, we should prepare spare parts with the same specifications as the original synchronous belt (including model, width, length, tooth shape, etc.). For chains, consider the number of links and size to match the original chain. Usually, 2-3 sets of belts and chains of each specification can be stocked.
Gears (including worm gears and worm wheels): As worm gears and worm wheels are subject to large forces during transmission, they are prone to wear and tear and need to be prepared with corresponding spare parts. For other gears, such as reduction gears, should also be stocked. The stocked gears should be the same as the original gears in terms of modulus, number of teeth, pressure angle and other parameters, and 1 - 2 of each kind of gears can be stocked.
Shafts and bearings:
Shafts: For critical drive shafts, especially those connected to the worm gear, prepare spare shafts. The size (diameter, length, etc.), accuracy level and material of the spare shaft should be the same as the original shaft. Depending on the degree of fragility of the shaft, 1 - 2 can be stocked.
Bearings: Different types of bearings are used in different locations, so it is necessary to stock various types of bearings. For example, deep groove ball bearings, tapered roller bearings, etc., 3 - 5 sets of each type of bearings should be stocked, because the bearings will be easily worn or damaged under long-term high-speed operation.
Fixture and positioning device:
Fixture: The collets and positioning pins of the fixture are in direct contact with the workpiece and are prone to wear and deformation. Prepare a variety of specifications of fixture collets and positioning pins, the number can be determined according to the fixture frequency of use and the degree of fragility, generally reserve 5 - 10 of each specification.
Positioning blocks and holders: If the positioning blocks and holders are worn or damaged, the accuracy of the assembly will be affected. Reserve the same specifications as the original equipment positioning block and seat, each can reserve 2 - 3.
2. Electrical Components
Motors and drives:
DC motors: Reserve 1 - 2 sets of spare DC motors. The power, speed, torque and other parameters of the motors should be the same as those of the original motors. Although the motors are relatively durable, they will affect production when they fail, so preparing them in advance can shorten the downtime.
Motor Driver: The driver is the key equipment to control the operation of the motor, and its parameters should be matched with the motor. Reserve 1 - 2 drives for timely replacement in case of drive failure.
Sensors:
Photoelectric sensors and proximity sensors: these two types of sensors are used in assembly machines to detect part position and status. Stock 2 - 3 photoelectric sensors and proximity sensors per model as they are susceptible to failure due to environmental factors (e.g. dust, oil).
Encoders: If the machine uses encoders to measure the position and speed of motors or robotic arms, stock 1 - 2 encoders to ensure that their resolution, accuracy, and other parameters are the same as the original encoders.
Controllers and relays:
Programmable Logic Controller (PLC) Modules: Depending on the complexity of the machine's control system, stock up on some commonly used PLC Input/Output (I/O) modules, such as Digital I/O Modules and Analog I/O Modules, and stock up on 1 - 2 of each.
Relays and contactors: These components play a key role in circuit control and are prone to problems such as contact wear. Reserve 3 - 5 relays and contactors of each type, and their rated current, voltage and other parameters should be matched with the original equipment.
3、Other parts
Lubrication and sealing materials: Reserve enough lubricating oil and grease, and their models should be consistent with the requirements of each lubrication part of the machine. For sealing materials, such as oil seals, seals, etc., reserve a variety of specifications of spare parts, the number of machine seals according to the number of parts and the degree of vulnerability to determine the general specifications of each reserve 5 - 10.
Fasteners and connectors: including all kinds of screws, nuts, washers, keys, etc., reserve different specifications of fasteners, the number can be determined according to the frequency of use on the machine and the type of determination, generally each specification reserve 20 - 50.
Second, to protect the inventory setup method
1、Assessment based on frequency of use and failure rate
Collect data: record the frequency of replacement of each component and the number of failures, which can be obtained through the equipment maintenance records and production operation data. For example, a certain type of belt needs to be replaced every 3 months on average, and a sensor fails 2 times per year on average.
Determine inventory levels: Set up a guaranteed inventory based on the frequency of use and failure rate of components. For the use of high frequency, failure rate is also high parts, such as fixture chuck, to protect the stock can be set to meet the number of 2 - 3 months of production needs; for the use of less frequent but the impact of failure of the components, such as motor drive, to protect the stock can be set to ensure that the equipment in the waiting for the purchase of new parts during the normal operation of the number of, generally 1 - 2.
2, consider the procurement cycle and supply stability
Procurement cycle survey: to understand the procurement cycle of spare parts, including the supplier's production time, transportation time and so on. For parts with long procurement cycle, such as customized gears or special specification motors, increase the guaranteed stock. For example, if the procurement cycle of a component is 3 months, the guaranteed stock should be able to meet at least the quantity required for the normal operation of the machine during these 3 months, and then consider a certain margin, e.g. 10% - 20%.
Evaluation of supply stability: Evaluate the supply stability of the supplier, and increase the guaranteed stock for parts with unstable supply. At the same time, looking for alternate suppliers to reduce the supply risk.
3、Cost and storage space balance
Cost analysis: Consider the cost of spare parts. For expensive parts, such as motors and drives, reasonably control the quantity of guaranteed stock under the premise of ensuring the timeliness of equipment maintenance. You can reduce the cost of inventory by negotiating with suppliers for emergency purchase prices and establishing leasing mechanisms.
Storage space planning: According to the actual space size of the warehouse, rationally plan the storage location and method of spare parts. Adopt scientific inventory management methods, such as ABC classification method (spare parts are classified into A, B and C categories according to their importance and capital consumption, with focus on managing category A, general management of category B, and simple management of category C), to optimize the setup of guaranteed inventory. At the same time, we utilize the information system to manage the inventory in real time and grasp the inventory dynamics in a timely manner.
※ If you need any help, please contact the technical specialist of Xinhui Electromechanical Equipment Co.
