Chinese Mechanical Engineering Society, Ministry of Education Examination Center Mechanical Engineer Qualification Examination Syllabus (Trial) Preface
Ⅰ. Basic Requirements
Ⅱ. Examination Contents
Ⅲ. Relevant regulations and instructions
IV. Preface to the sample questions
The "Mechanical Engineer Qualification Examination Syllabus" (Trial) is developed by the Chinese Mechanical Engineering Society and the Examination Center of the Ministry of Education. One of the examination standard documents formulated for the technical qualification certification of mechanical engineering technicians in my country. It is the basis for the review and preparation of the "Comprehensive Quality and Skills" exam for applicants for mechanical engineer qualification certification. It is the basis for compiling study materials such as the "Mechanical Engineer Qualification Examination Guide", the basis for carrying out student tutoring in various places, and the basis for the qualification examination. The basis for the proposition.
This syllabus*** is divided into four parts: Ⅰ. Basic requirements, Ⅱ. Exam content, Ⅲ. Relevant regulations and instructions, Ⅳ. Sample questions.
The basic requirements section aims to show that as a qualified mechanical engineer, you should actively adapt to the development trend of globalization, informatization, greenness and service-oriented manufacturing in the world today, and strive to improve your overall quality. , to become a new generation of mechanical engineering professional technicians with good professional ethics and innovative ideas, mastering mechanical manufacturing technology, understanding economics, management knowledge and relevant international principles.
The examination contents listed in the syllabus reflect eight aspects of basic knowledge, relevant knowledge and skills that a qualified mechanical engineer should possess. The content of these examinations not only covers the main basic and professional knowledge learned in university, but more importantly, it includes the practical experience and abilities that candidates should acquire by applying this knowledge after working. It also involves new knowledge that should be expanded after graduating from university. A comprehensive assessment of the overall quality of the candidates. Therefore, if candidates want to pass the qualification examination and meet the basic requirements set out in the syllabus, they must have a solid university foundation, solid work practice after graduation, and continuous accumulation of continuing education while working.
Part III of the syllabus is the relevant regulations and instructions on the examination format, time, precautions, structure of the examination paper, question distribution, question type and amount, difficulty level, etc. of the qualification examination.
Part IV of the syllabus provides sample questions for the first and second unit exams. This syllabus needs to be further improved and perfected after passing a stage of examination practice. We hope that users can provide comments and suggestions.
Return to I. Basic requirements
1. Proficient in engineering drawing standards and representation methods. Master the selection and labeling of tolerance fits.
2． Be familiar with the properties, test methods and selection of commonly used metal materials. Master the heat treatment principles of steel and be familiar with the heat treatment methods and selection of commonly used metal materials. Understand the types and applications of commonly used engineering plastics, special ceramics, optical fibers and nanomaterials.
3. Master the basic knowledge and skills of mechanical product design, and be able to design parts and components proficiently. Be familiar with the design procedures and basic technical elements of mechanical products, be able to use computers to assist in the design of parts, be familiar with practical design methods, and understand modern design methods.
4. Master the basic knowledge and skills of formulating process processes, be able to skillfully formulate processing processes for typical parts, and be able to analyze and solve general process problems that occur on site. Be familiar with the basic technical content, methods and characteristics of mechanical manufacturing processes such as casting, pressure processing, welding, cutting (grinding) processing, special processing, surface coating treatment, assembly, etc. and master certain key points. Familiar with the design knowledge of process plans and process equipment. Understand the principles and knowledge of production line design and workshop layout.
5. Familiarity with safety regulations, ethics and laws relevant to the profession. Familiar with the basics of economics and management. Understand the concepts and applications of management innovation.
6． Be familiar with quality management and quality assurance systems, master the basic tools and methods of process control, and understand relevant quality inspection technologies.
7. Familiar with basic knowledge of computer applications. Familiar with the composition, function and control program preparation of computer numerical control (CNC) systems. Understand the basic concepts of computer simulation and the characteristics and applications of commonly used computer software.
8. Understand the relevant knowledge of machinery manufacturing automation.
Return to Ⅱ. Exam content
1. Engineering drawing and tolerance coordination
1. General provisions for engineering drawings
(1) Drawing frames
(2) Drawing lines
(3) Proportions
(4) Title bar
(5) View representation method
(6) Layout of drawings
(7) Section symbols and drawing methods
2. The prescribed drawing method of parts and components (system) drawings
(1) The prescribed drawing method of parts and components drawings of mechanical systems (the drawing method of threads and threaded fasteners gears, racks, worms, worm gears and How to draw sprockets, how to draw splines and how to draw springs with dimensions)
(2) Schematic drawing of mechanical, hydraulic, and pneumatic system diagrams (simplified drawing of mechanical parts and components and Symbols: Simplified drawing methods and symbols for pipelines, interfaces and joints Simplified drawing methods and symbols for commonly used hydraulic components)
3. Schematic diagram
(1) How to draw the schematic diagram of the mechanical system
(2) How to draw the schematic diagram of the hydraulic system
(3) Pneumatic system schematic diagram
4. Schematic diagram
5. Dimension, tolerance, fit and geometric tolerance marking
(1) Dimension marking
(2) Tolerance and fit marking (basic concept tolerance and fit marking method)
(3) Geometric tolerance marking
6. Surface quality description and labeling
(1) Evaluation parameters of surface roughness
(2) Surface quality labeling symbols and codes
(3) Surface quality Notes on labeling
7. Dimensional chain 2. Engineering materials
1. Metal materials
(1) Material properties (mechanical properties, physical properties, chemical properties, process properties)
(2) Crystal structure (properties of crystals, crystal structure of metal, crystallization of metal, metal in solid state The structure of the transformed alloy under )
(4) Test method (tensile test, impact test, hardness test, chemical analysis, metallographic analysis, non-destructive testing)
(5) Material selection (usage performance, process performance, economy)
p>2． Other engineering materials
(1) Engineering plastics (commonly used thermoplastic engineering plastics, commonly used thermosetting engineering plastics, commonly used plastic molding methods, applications of engineering plastics)
(2) Special ceramics (alumina ceramic nitrogen Silicone ceramics, silicon carbide ceramics, boron nitride ceramics, cermets)
(3) Optical fibers (types of applications)
(4) Nanomaterials (types of applications)
3. Heat treatment
(1) Heat treatment process (heat treatment of steel, heat treatment of cast iron, heat treatment of non-ferrous metals)
(2) Heat treatment equipment (fuel furnace, resistance furnace, vacuum furnace, induction heating power supply)
(3) Heat treatment applications (shafts, springs, gears, rolling bearings, molds, tools, cast iron, steel castings, non-ferrous metal parts) 3. Product design
1. New product design and development procedures
(1) Feasibility analysis (market research product positioning feasibility analysis report)
(2) Concept design (design requirement functional analysis plan design design task statement) )
(3) Technical design (work content and requirements mechanical structure design calculation instructions)
(4) Design evaluation and decision-making (evaluation objectives, criteria evaluation methods)
2. Basic technical elements of mechanical design
(1) Strength and stiffness
(2) Structural process design (processability design, assembly design, key points of design principles for packaging and transportation)< /p>
(3) Reliability (Reliability Evaluation Index Reliability Design)
(4) Friction/Wear/Lubrication (Friction Law Wear Law Factors Affecting Friction and Wear Reduce Friction and Wear Methods)
(5) Mechanical vibration and noise (basic concepts of the root causes of vibration and noise and strategies and measures to prevent and reduce vibration and noise)
(6) Safety (Principles of safety design and protective design)
(7) Standardization and generalization
3. Design of mechanical parts and components
(1) Mechanical transmission and its parts and components (function of gears
Ability to characterize and design the functional characteristics of the shaft, design the functional characteristics of the screw, design the functional characteristics of the belt drive, design and calculate the functional characteristics of the reducer, and design and select the functional characteristics and design of the speed regulator)
(2) Connections and fasteners (the functional characteristics of bolted connections, the functional characteristics of design keys, the functional characteristics of design calculation pins, the functional characteristics of designed couplings, and the functional characteristics and design of interference connections)
(3) Operation adjustment and control parts (the functional characteristics of the spring and the functional characteristics of the designed clutch and the designed functional characteristics of the brake)
(4) Box/frame parts (box, Rack design guidelines, cabinet and rack design general requirements, cabinet and rack design steps)
4. Pneumatic and hydraulic transmission control systems
(1) Commonly used pneumatic and hydraulic components (control valves, pumps and motors)
(2) Pneumatic and hydraulic transmission principles and system design (pneumatic system Basic piping design Basic piping design of hydraulic system)
(3) Common fault diagnosis and maintenance
(4) Seal design
5. Basics of electrical transmission
(1) Electric motor (DC motor, asynchronous motor, synchronous motor)
(2) Electrical speed regulation (speed regulation of DC motor, speed regulation of asynchronous motor)
(3) Electric braking (DC motor braking, asynchronous motor braking)
(4) Selection of motors
6. Design methods and applications
(1) Computer-aided design (conceptual application)
(2) Practical design methods (industrial shape design optimization design ergonomics inverse technology modular design limited Meta-analysis, rapid prototyping)
(3) Modern design methods (parallel design, intelligent design, life cycle design, green design, innovative design) 4. Manufacturing process
1. Process design
(1) Basic concepts of process (production process, process, machining process, machining process specification)
(2) Basis, procedures and main principles of process specification design Problems (basis for process planning design, procedures for process planning design, main issues in process planning design)
(3) Product structure process review (product structure process review object, product structure process review purpose, product structure) The main factors that should be considered during the process review (product structure process review content)
(4) Selection of positioning benchmark (concept of benchmark, selection of fine benchmark, selection of rough benchmark)
( 5) Process route design (selection of surface processing method, division of processing stages, arrangement of processing sequence, reasonable combination of processes)
(6) Determination of machining allowance (determination of factors affecting machining allowance concept) Method of machining allowance)
(7) Process size calculation (basic concept of process size chain, basic process size chain solution, comprehensive process size chain chart calculation method)
( 8) Technical and economic analysis of process plans (evaluation principles of process plans, analysis and comparison of process plans)
(9) Examples of typical part process design (processing technology of box parts, spindle processing technology, cylindrical gear processing technology )
2． Design and manufacturing of process equipment
(1) Process equipment and its types (types of process equipment)
(2) Basis for selection of process equipment (process plan, process procedure, process Requirements and equipment The existing process equipment conditions of the enterprise (standards, ordering manuals, atlases and instructions for use of various process equipment, etc.)
(3) Principles for the selection and design of process equipment
(4) Process equipment selection procedures
(5) Process equipment design procedures
(6) Technical and economic evaluation indicators for process equipment design (or selection)
(7) Process equipment verification (purpose of process equipment verification, scope of verification, main content of verification, method of verification)
3. Workshop graphic design
(1) Workshop production equipment layout principles
(2) Product type and production analysis (equipment layout plan by product (or assembly line, production line) by type of work (or Specialized) equipment layout plan (group (or unit) equipment layout plan)
(3) The layout of workshop equipment (cluster layout and assembly line layout)
4. Cutting (grinding) processing
(1) Cutting (grinding)
) Basic knowledge of turning processing (basic concepts of metal cutting rate, cutting force, cutting heat and cutting temperature, tool wear and tool durability, cutting processing methods and characteristics, economical processing accuracy)
(2) Turning (commonly used turning methods, typical turning Processing surface type Lathe type and application range Typical turning processing (non-CNC turning method) New turning technology)
(3) Milling (common milling methods Typical milling processing surface type Milling machine type and application range Typical parts Surface milling and ultra-precision milling)
(4) Grinding (commonly used grinding methods, typical grinding processing surface types, main grinder types and application range, typical part surface grinding)
( 5) Factors affecting the quality of cutting (grinding) and improvement measures (factors in the process system, factors in the process, environmental factors, principles and measures to improve the quality of the cutting)
(6) Selection of cutting amount< /p>
(7) Tool fixtures for cutting (machine tool fixture cutting tools)
5. Special machining
(1) Special machining methods and characteristics
(2) Electrical discharge machining (electrical discharge forming processing). The process of electric discharge forming processing and the impact of electric discharge forming processing machine tools on electric discharge forming Factors and improvement measures for the quality of processing technology)
(3) Wire-cutting EDM (Characteristics of wire-cutting EDM, process of wire-cutting EDM, main process of wire-cutting EDM equipment) Factors and analysis of quality indicators affecting process economy)
(4) Laser processing (laser processing principles, characteristics and classification of laser processing equipment, laser drilling and laser cutting)
(5) Ultrasonic processing (principles and characteristics of ultrasonic processing, ultrasonic processing equipment, ultrasonic processing process parameters and their influencing factors, application of ultrasonic processing)
6. Casting
(1) Casting and its characteristics (Basic Casting Process Design Casting Process Document)
(2) Sand Casting (Molding Material Casting Iron Casting Casting Steel Casting Casting Copper, Aluminum alloy casting casting)
(3) Metal mold casting (copper alloy casting, aluminum alloy casting)
(4) Die casting (structural die casting alloy die casting machine for die castings)
(5) Investment casting (structure of investment casting, process parameters of investment casting, characteristics and application of model shell)
(6) Casting process equipment (pattern template, core box, sand box)
7. Pressure processing
(1) Pressure processing and its classification (the meaning and characteristics of pressure processing, classification and application of pressure processing)
(2) Forging (free forging)
p>(3) Stamping (Characteristics of Stamping Processing, Classification of Stamping Process, Application Requirements of Stamping Process)
(4) Factors affecting the quality of forging processing and measures to improve it
(5) Process equipment for pressure processing (stamping die design, hot forging die design, tire mold structure design, rapid and economical molding technology)
8. Welding
(1) Welding methods and characteristics (basic arc welding power source and characteristic welding process of fusion welding process)
(2) Arc welding (hand arc welding and its equipment submerged arc Welding)
(3) Argon arc welding
(4) Gas welding (selection of gas welding process parameters for gas welding and gas cutting equipment)
(5) Welding process equipment (welding fixtures, welding auxiliary processing devices, welding manipulators)
9. Surface treatment
(1) Characteristics and classification of surface treatment (classification of surface treatment characteristics and surface engineering technology)
(2) Coating technology (coating materials, coating technology and equipment coating Evaluation of coating film quality of typical products of film drying)
(3) Thermal spray technology (Commonly used thermal spray process classification and thermal spray technology characteristics Thermal spray process flow Thermal spray process method Thermal spray material Thermal spray technology Quality assessment of applied thermal spray coatings)
(4) Electroplating (implementation of electroplating, process of electroplating, factors affecting coating quality, type of electroplating and quality evaluation of applied electroplating)
10. Assembly
(1) Basic knowledge (assembly, subassembly, final assembly assembly unit, reference parts and reference components, reference component assembly accuracy and the main factors affecting assembly quality)
(2) Assembly dimension chain and assembly method (assembly dimension chain assembly method)
(3) Assembly method types and their selection (complete interchange assembly method, partial interchange assembly method (also
Called large number interchange assembly method) Select assembly method Modify assembly method Adjust assembly method)
(4) Typical component assembly (rolling bearing component assembly cylindrical gear transmission component assembly) 5. Management/Economy
1． Safety/Environmental Protection
(1) Equipment maintenance (maintenance) and safe operation (maintenance of equipment (maintenance), safety technology for processing and lifting machinery, safety robots, CNC machine tools and automatic production lines)
p>(2) Common labor safety and health precautions (fire prevention, explosion protection, electric shock prevention, static electricity prevention and noise prevention)
(3) Environmental protection (industrial waste gas, waste water, solid waste and their treatment technology Environmental protection laws, regulations and standards Clean production ISO14000 environmental management series standards introduction)
2. Moral and legal knowledge related to the profession
(1) Basic moral standards for citizens
(2) Main contents of citizen moral construction
(3) Mechanical engineers Code of Professional Ethics
(4) Financial and tax system (basic accounting system, three financial statements, tax types, tax rates)
(5) Intellectual Property Law (Basic Knowledge Patent Law, Trademark Law, Copyright Law Anti-Unfair Competition Law)
(6) Laws related to modern enterprise systems (Company Law, Contract Law, Tendering Law, Production Licensing System)
(7) WTO rules and government industrial policies ( History and my country’s commitments: WTO basic principles, WTO’s four major purposes, countervailing and anti-dumping, and the impact of joining the WTO on Chinese society)
3. Engineering Economy
(1) Basic concepts of economics (demand supply supply and demand balance market market economy command economy and mixed economy)
(2) Cost analysis (classification amount of cost- The relationship between costs and profits - cost-profit analysis)
(3) Value engineering (basic concept of value engineering, basic procedures for implementing value engineering, product function analysis, product function evaluation, proposing improvement ideas, analysis and evaluation plan Test, inspect, evaluate effects)
4. Management
(1) Basic functions of management (the importance of management and the basic functions of work nature management)
(2) Modern enterprise system (separation of two rights of enterprise ownership, enterprise property organization Form corporate governance structure)
(3) Productivity analysis and improvement (productivity method research time study proficiency curve)
(4) Logistics foundation (basic concepts of logistics and its system manufacturing enterprises Characteristics of commonly used material handling equipment in logistics systems and selection of supply chain and supply chain management)
(5) On-site management (5S activity placement management)
5. Management Innovation
(1) Changes in manufacturing models and advanced manufacturing models (manufacturing models start from mass production to group technology, CNC technology and unit manufacturing - solutions to multi-variety batch production to contemporary advanced manufacturing Mode)
(2) MRP/MRPⅡ/ERP (MRPMRPⅡERP)
(3) Lean production (just-in-time (JIT) production Kanban management)
( 4) Project management (project and project management concepts, three elements of project management and goals, process and content of project management)
(5) Agile manufacturing (the background of agile manufacturing strategy, the basic concept of agile manufacturing strategy) Enterprise agility case) 6. Quality management/quality control
1. Quality management/quality assurance
(1) Quality/product quality (quality definition product quality and quality characteristics formation of product quality and quality functions and responsibilities)
(2) Quality management and Total quality management (the meaning of quality management, the development of quality management, the characteristics of total quality management, the basic work of total quality management)
(3) ISO9000 family standards and quality system (the generation and development of ISO9000 family standards ISO9000 family The composition and content of standards, quality assurance and quality system establishment)
(4) Quality certification (types of quality certification, product quality certification, quality system certification)
2. Process quality control
(1) Concept of quality control
(2) Basic tools of process quality control (statistical analysis table, Pareto chart, cause-and-effect diagram)
(3 )Statistical process control tools (histogram process capability and process capability index Cp control chart)
(4) Correlation analysis (correlation diagram (scatter plot) method regression equation method correlation analysis
The use of analysis in quality control)
3. Measurement and Inspection
(1) Measurement and Inspection in Product Manufacturing
(2) Geometric Quantity Measurement (Measuring Reference Instruments for Length Measurement Angle Measuring Instruments Shape Measuring Instruments)
p>
(3) Mechanical quantity measurement (measurement of force and weight, measurement of torque, displacement measurement, rotational speed measurement, vibration measurement)
(4) Measurement of other physical quantities (temperature measurement, pressure measurement, noise measurement) 7. Computer Applications
1. Basic knowledge of computer applications
(1) The composition and types of microcomputers
(2) The structural and performance characteristics of commonly used microcomputers (the structural and performance characteristics of sixteen-bit microcomputers (8086/8088CPU) Structural and performance characteristics of the eight-bit microcomputer (Z80CPU) Structural and performance characteristics of the single-chip microcomputer I/O interface and memory expansion programmable logic controller (PLC))
(3) Selection principles of microcomputer software and hardware
p>2． Computer simulation
(1) Basic concepts of simulation
(2) Development and significance of computer simulation
(3) General process of computer simulation
(4) Application of simulation in CAD/CAPP/CAM system
3. Computer Numerical Control (CNC)
(1) Basics of CNC control programming (content and steps of CNC machining programming, common program format and typical program code)
(2) CNC program Programming methods (manual programming and automatic programming, manual programming examples, programming language methods, automatic programming processes, and APT programming simple examples, ordinary program formats)
(3) Linear interpolation and arc interpolation
4． CAD/CAPP/CAM/CAE
(1) Basic concepts of CAD/CAPP/CAM
(2) Basic functions and workflow of CAD/CAPP/CAM
(3) Computer-aided design (CAD)
(4) Computer-aided process design (CAPP)
(5) Computer-aided manufacturing (CAM)
(6) Application status of CAD/CAPP/CAM
(7) Computer Aided Engineering (CAE) 8. Mechanical manufacturing automation
1. Development of machinery manufacturing automation and its technical content classification
2. Automation of processing operations (equipment automation)
(1) Rigid automated processing equipment (ordinary automated machine tool combination machine tool rigid automatic line)
(2) Flexible automated processing equipment (CNC machine tool machining center )
3． Logistics automation
(1) Logistics concepts and functions
(2) Logistics automation equipment classification (loading and unloading/loading and unloading automation equipment transmission/handling automation equipment storage automation equipment)
p>
4． Information flow automation
(1) Information meaning and information flow/information system
(2) Information source
(3) Information collection/input
(4) Information processing
(5) Information transmission and exchange
(6) Information storage
5. Management automation
(1) Management meaning and its automation basis
(2) MRP-II
6. Common flexible automation systems for mechanical manufacturing
(1) DNC system
(2) FMC (flexible processing cell)
(3) Flexible automatic line (FTL)
(4) FMS (Flexible Manufacturing System)
(5) Computer Integrated Manufacturing System (CIMS) III. Relevant regulations and instructions
1. Exam format
The Mechanical Engineer Qualification Examination is divided into two units, both of which are written examinations.
The exam time for the first unit is 3 hours. Candidates must answer all questions in the test paper. Candidates are required to bring a calculator, set square and compass.
The exam time for the second unit is 2 hours. The test paper contains compulsory and optional questions. Candidates can bring the "Mechanical Engineer Qualification Examination Guide" and need to bring a calculator, set square and compass.
The full score of the first unit test paper is 120 points, and the full score of the second unit test paper is 80 points. The sum of the full marks for the two units is 200 points, and 120 points is a passing mark.
2. Propositional Principle
1. The propositions are based on this outline.
2． The examination questions cover all examination contents stipulated in this syllabus, appropriately highlight key contents, and increase the coverage density of key contents. The focus of this syllabus is the design/manufacturing and management/economics (including quality management) parts.
3. Strengthen the assessment of application ability, that is, focus on assessing the candidates' ability to use the knowledge they have learned to analyze and solve practical problems, focusing on application and practical questions.
4. The exam question types are multiple choice questions, simple application questions and comprehensive application questions. The first unit exam paper contains 80-point multiple-choice questions and 40-point simple application questions, with a full score of 120 points; the second unit exam paper contains 40-point simple application questions (candidates must answer) and 40-point comprehensive questions. Application questions (selected by candidates), with a full score of 80 points. Comprehensive application questions will be divided into two areas: design/manufacturing and management/economics.
5. Multiple-choice questions mainly test basic knowledge and basic skills at the "understanding", "familiar" and "mastery" levels; application questions mainly test candidates' use of "familiar" and "mastery" level knowledge to carry out task analysis, discussion, calculation and drawing. and basic abilities in simple design.
6. Questions of different difficulty levels are reasonably arranged in the test paper. The score ratio for questions of different difficulty (easy, easier, harder, difficult) in each test paper is generally 2:3:3:2.
3. Tutoring materials and reference books
"Mechanical Engineer Qualification Examination Guide" Technical Qualification Certification Center of the Chinese Mechanical Engineering Society
"Mechanical Engineer Continuing Education Series" 》Related volumes: Mechanical Engineer Continuing Education College
Related teaching books for undergraduates in mechanical manufacturing and automation, industrial engineering, management engineering and other majors. Return to IV. Sample Questions Unit 1
1. Multiple Choice Questions
1. It has the best plasticity, high tensile strength, high elongation and minimal deformation. The engineering plastics suitable for products that require injection molding are
A) Polycarbonate B) Polystyrene C) Phenolic plastic D) Epoxy resin 2. The purpose of the riser in the casting mold is
A) to help lift the mold B) to be fixed with the upper mold box
C) to enhance the draft angle D) to replenish metal when the casting is cooling 2. Simple Application questions
The following steps are the basic methods for formulating the processing technology of general parts. They are: process analysis, selecting blanks, determining the machine tools for each process, determining the machining allowance for each process, preparing process cards, and formulating the process. Sequence, technical requirements analysis, ***7 items (the order has been disrupted), please arrange them in a reasonable order and briefly explain the work content. Unit 2
1. Simple application questions
1. The picture below shows a piston supported on a threaded end cap. Try to analyze what problems exist and how to improve them (draw an improvement diagram). 2. Comprehensive application questions
1. Gears are the most commonly used transmission parts in machines. They are generally required to have smooth transmission, high strength, deep hardening layer, wear resistance and dimensional stability. If it is a mass-produced cylindrical gear, what kind of material should be selected and what method should be used to make the blank? What should be the flow of the entire process (including cold and hot processing)? Why? 2. The size processing requirements for a part are as follows: 50 samples are processed on an ordinary lathe, and the resulting dimensions are as shown in the table: