CNC Turning

WorldSkills Occupational Standards (WSOS)

Occupation description and WSOS

The name of the skill competition is

CNC Turning

Description of the associated work role(s) or occupation(s)

CNC Machining has become one of the most important current machining processes in modern industry. Parts are made for household-equipment, telecommunications, cars, ships, aeroplanes, oil rigs, bridges, aerospace etc. Customers come from virtually every sector.

CNC Machining covers a broad variety of machining processes, such as grinding, welding, electrical discharging, milling and also turning or turn-milling.

The CNC Machinist dictates the entire production-process through the choice of setup, tools and movements through their programming. Once correctly programmed and set up, these machines can produce almost any shape and can repeat the process infinitely. This offers great advantages for quality and efficiency.

Some may think that lathes (turning machines) are built to make only round parts; however, CNC lathes are capable of producing almost any shape and any part, especially with CNC-turn-mill machines.

Different requirements and demands are required for each customer application. Therefore workpieces are made of different materials with different properties and different geometries, tolerances and surface qualities. In order to provide the machinist with all the information they need, there is a technical drawing (finished part drawing) in digital or paper form for each workpiece. The digital data of the required part can be imported in software, which makes it a lot easier to achieve the desired geometry. Hoewer, the machinist must thoroughly check if and how the geometry can be achieved.

Machining starts with deciding how best to produce the part. There are many ways of doing this, like welding, milling, casting, and 3D Printing. One very important method is CNC Turning.

A CNC lathe is a very accurate computer-driven machine, where cutting tools, controlled by a program, are moved to cut away excess material to result in the expected work piece. The CNC Turning machinist receives the technical drawing and uses the lathe in many ways to find solutions to build the part. These machines are very expensive, because they can do remarkable things. To have an idea of this, think what it means to achieve accuracy below ten microns, which is six to10 times thinner than a human hair.

The CNC Turning machinist uses a computer to tell the lathe how to move the tools and cut the part to the desired shape. They must also set up the lathe with all the necessary clamping devices, support devices, and cutting tools. These tools can cut almost every material (stainless steel, plastic, soft steel, aluminium, bronze, and so on). But the machinist has to choose well to avoid temperature variations, tool wear and vibration. Those factors influence the product and can result in poor quality.

When the machine starts cutting material, the machinist must ensure that all dimensions exactly fit the workpiece specifications. This may require some modifications and very accurate inspection tools must be used. Once the machine is set up, the CNC-Turning machinist also monitors and optimizes the processes, to achieve even faster and better results for all the following parts.

When makeing very complex parts, the CNC Machinist sometimes must read and understand drawings that have been measured with GPS and transfer the data to the control of the machine.

Problem-solving strategies, logical thinking, a high sense of precission, and the understanding of technical communication are the basic requirements for the CNC Lathe Machinist,

The WorldSkills Occupational Standards (WSOS)

General notes on the WSOS

The WSOS specifies the knowledge, understanding, skills, and capabilities that underpin international best practice in technical and vocational performance. These are both specific to an occupational role and also transversal. Together they should reflect a shared global understanding of what the associated work role(s) or occupation(s) represent for industry and business (www.worldskills.org/WSOS).

The skill competition is intended to reflect international best practice as described by the WSOS, to the extent that it can. The Standard is therefore a guide to the required training and preparation for the skill competition.

In the skill competition the assessment of knowledge and understanding will take place through the assessment of performance. There will only be separate tests of knowledge and understanding where there is an overwhelming reason for these.

The Standard is divided into distinct sections with headings and reference numbers added.

Each section is assigned a percentage of the total marks to indicate its relative importance within the Standards. This is often referred to as the “weighting”. The sum of all the percentage marks is 100. The weightings determine the distribution of marks within the Marking Scheme.

Through the Test Project, the Marking Scheme will assess only those skills and capabilities that are set out in the WorldSkills Occupational Standards. They will reflect the Standards as comprehensively as possible within the constraints of the skill competition.

The Marking Scheme will follow the allocation of marks within the Standards to the extent practically possible. A variation of up to five percent is allowed, if this does not distort the weightings assigned by the Standards.

WorldSkills Occupational Standards

Section		Relative importance (%)
1	Work organization and management	5
	The individual needs to know and understand: The scope and limits of the workshop and the workspace Standards for the environment, safety, hygiene, and prevention of accidents When and how to use safety equipment, such as first aid kits, fire extinguishers Types of energy supplies for the CNC Lathe (electric, hydraulic, pneumatic) and their sustainable management Basic machine maintenance (Coolant-Maintenance, Machine-Lubrication, settings etc.) Machine accessories such as clamping devices, tailstock, and part-catching devices The use and care of the available computer operating systems Programming, setting, and operating of CNC lathe with live tooling and multiple axes CNC-programming systems (Din-ISO (G-Code writing), CAM software) Principles of technical design and process planning Properties of ferrous and nonferrous materials Mathematics - Geometry, especially calculations in trigonometry Principles of cutting- and chip-removal technology The importance of effective communications and teamwork How to liaise with supervisors and team members The proper and efficient use of machinery-handbooks, datasheets and manufacturers’ operating instructions The calibration, accuracy-limits and the use of measurement- and gauging tools.
	The individual shall be able to: Organize the workspace for optimal safety and performance Check the condition and functionality of the workspace, equipment, tools and materials Interpret and apply quality standards and regulations Promote and apply health and safety regulations and best practice Liaise with supervisors and team members as required and helpful Set up and operate CNC lathes in a safe and environmentally well managed manner (e.g. in use of energy) Select and use appropriate professional software Apply mathematical and geometrical principles for programming processes Select and apply appropriate cutting technology for the material, equipment, and cutting tools provided Select and apply appropriate clamping methods Select and apply the proper use of machine acessories ( e.g. parts catcher, tailstock etc ) Interpret and apply manufacturers’ instructions Find appropriate data in handbooks, tables, and charts.
2	Interpret engineering drawings	10
	The individual needs to know and understand: ISO E and/or ISO A (European and American) drawing representation Technical terms and symbols used in engineering drawings and plans Related standards, symbols, and datasheets Geometric dimensioning and tolerancing (ISO Standard) Technical drawing-legends.
	The individual shall be able to: Interpret engineering drawings and apply to specifications Locate and identify dimensions of features Locate and identify surface finish requirements Locate and identify geometric specifications Make 3D mental representations of the projects requested on the drawing Identify the materials that parts are made of Identify critical sequences (with a high possibility of damage or unsafe practice) and develop appropriate approaches.
3	Process planning	10
	The individual needs to know and understand: The importance of good planning for reliable machining operations The procedures and calculations required for scheduling time for programing and machining Successful timing of selected sequences Methods for Identiying critical sections The behaviour of machines, clamping devices, materials, tools, and machine accessories in different cutting processes Methods and techniques for work holding Methods to avoid crashes or collisions for the selected sequences Sustainability: methods to ensure best material use, energy use and waste management Safe practice methods and plans for safety awareness for others if applicable Appropriate actions to avoid heavy toolwear The identification of workpiece features and the appropriate machining and measuring processes.
	The individual shall be able to: Find solutions using the capacities of the workshop environment, and according to the required work (size of batch, complexity) Identify the appropriate machining and measuring processes for each feature of each work-piece Identify and prepare the best (safest) work holding methods Identify, prepare, and calibrate appropriate measuring tools Identify and prepare appropriate cutting tools Identify critical sections (with a high possibility of damage or unsafe practice) and pick alternatives or safe practices to avoid accidents or damage Apply methods for best material use to avoid exsessive waste Find innovative ways of using the environment to solve technical issues Find alternatives which will be reliable for each entire process Weigh each solution and choose the best (considering context, speed, safety, price, and sustainability) Make a final choice and lock the strategy accordingly Plan the operations and sequences (workholding and machining strategy) based on specified data Create awareness actions for critical operations where no alternative is available If necessary, create safety awareness or measures for others around the machine (e.g. safety or caution tape) Create an action plan for toolwear control.
4	Programming	10
	The individual needs to know and understand: CNC programming as the creation of a logical process plan Different methods and techniques to generate programmes (manual, CAM, etc.) CAM system programming and the techniques of part- and tool-modelling Cutting-effect (temperature, vibrations, bending, force, etc.) on: Geometry of the work piece design Work holding devices Tool holding devices Tool wear Machine-accessories The selection of cutting tools for machining the required material and features Mathematics (especially geometry/trigonometry) Appropriate speeds and feeds for different materials and tools and work holding devices The basis for choosing correct postprocessors The generation of G-Code Dialoguing with the CNC Lathe (wireless technology, cables, memory devices etc.) The proper use of canned cycles to programme work piece features (classical turning features as well as driven-tool features) Selection of suitable simulation options and simulation of the CNC programmes for the detection of process-critical and non-optimal machining on the workpiece.
	The individual shall be able to: Select and programme the best methods according to the production type and part specifications Use skill-specific software and related hardware Generate programmes using CAD/CAM systems Create or edit programmes directly on the machine-control Edit running programmes in CAD/CAM and reload to the machine-control Use the proper simulation method of the CNC programme to avoid any unwanted (unexpected) errors Document any related optimizations and up-load the optimized CNC programme to the company-server.
5	Metrology	5
	The individual needs to know and understand: The properties, uses, and handling of ferrous and non-ferrous materials Different Material-Identification-Norms (DIN, ISO, ASI, SAE etc.) The chip removal behaviour of provided materials and tools The temperature-related behaviour of provided materials, tools and machine-accessories during the machining process The effects of cutting force on material, clamping-devices, tools, and machine-accessories The range of tools and gauging instruments as well as their applications The influence of temperature and/or surface quality on measurements.
	The individual shall be able to: Identify the materials and their properties by DIN-, ISO-, AISI- SAE- or any other national norm and name (with the use of tables or machinery handbooks or other means) Select and use appropriate cutting and clamping tools for the provided material React accordingly to arising cutting forces, temperature problems, vibrations and other manufacturing-disturbing-factors Select appropriate measuring and/or gauging instruments Calibrate related measuring tools Properly use the selected inspection tools to make measurements on all features of the products.
6	Setting and operating CNC lathes	55
	The individual needs to know and understand: The different steps and sequences that lead to the setup of the machine The different modes of machine operation The appropriate power up and Initializing sequence of CNC lathes The proper manipulating of CNC lathes Mounting tools and setting tool parameters The modification of clamping devices, such as jaws, dual spindle etc The transfer of CNC programmes to machine control or back to the company-server, using provided software, cables, memory devices, or wireless technology The testing of CNC programmes (simulation, dry run, etc.) The correct, efficient and safe clamping of workpieces Settings of work shift and tool shift offsets The safe running of CNC procedures Stopping and restarting cycles Emergency stopping.
	The individual shall be able to: Follow the selected process strategies Appraise and follow a given process strategy when using external CNC programmes Upload generated CNC programmes to CNC lathes and perform test runs Identify and designate the different machining processes on CNC lathes Mount and align selected tools Mount and align selected work holding devices Mount and align selected accessories (Tailstock, Parts-catcher, etc.) Set measures to avoid vibration in machining sequences Apply efficient burr-removal techniques on work pieces Optimize machining strategies Avoid or optimize toolwear React quickly and appropriately to problems and emergencies Obtain dimensions, geometries, surface roughness etc. from each workpiece Make all necessary corrections to get the final part to conform to the blueprint Report health, safety, and environmental issues to the appropriate personnel Report equipment failures to the appropriate personnel.
7	Finalize and deliver work pieces	5
	The individual needs to know and understand: Appropriate procedures with documentation for re-using jobs The importance of completing work pieces to the required standard within their capabilities The circumstances in which referral should be made to other appropriate personnel.
	The individual shall be able to: Clean and deburr products Make final optical and measurement checks Dismount tools, clamping devices and machine accessories Clean the machine and workplace Set each environment to their initial state, ready for the next job Document and save CNC Programs, work-holding and tooling information etc. for each organization’s re-use of a production Deliver related documentation, parts, drawings, CNC Procrams and digital memory devices to the appropriate locations and/or personnel as required by the organization.
	Total	100

References for industry consultation

General notes

WorldSkills is committed to ensuring that the WorldSkills Occupational Standards fully reflect the dynamism of internationally recognized best practice in industry and business. To do this WorldSkills approaches a number of organizations across the world that can offer feedback on the draft Description of the Associated Role and WorldSkills Occupational Standards on a two-yearly cycle.

In parallel to this, WSI consults three international occupational classifications and databases:

ISCO-08: (http://www.ilo.org/public/english/bureau/stat/isco/isco08/)
ESCO: (https://ec.europa.eu/esco/portal/home )
O*NET OnLine (www.onetonline.org/)

References

This WSOS appears most closely to relate to “lathe and turning machine tool setters, operators, and tenders, metal and plastic”:
https://www.onetonline.org/link/summary/51-4034.00

and/or “lathe and turning machine operator”
http://data.europa.eu/esco/occupation/63042e8f-dd59-47fe-87f3-3b2ce21f196a

Adjacent occupations can also be explored through these links.

ILO 7223

The following table indicates which organizations were approached and provided valuable feedback for the Description of the Associated Role and WorldSkills Occupational Standards in place for WorldSkills Lyon 2024.

Organization	Contact name
CHIRON Group SE	Herbet Mattes, Head of Training
DMG MORI	Joerg Harrings, Head of Training Division
DMG MORI SINGAPORE PTE. LTD.	Kevin Goh, Technical Director