Producing mechanical engineering drawings using computer aided techniques
Overview
This standard identifies the competences you need to set up and operate a computer aided drawing (CAD) system to produce fully detailed drawings for mechanical engineering activities, in accordance with approved procedures. The drawings produced will include detail component drawings for manufacturing, assembly and sub-assembly drawings, installation drawings, and fault location aids such as flow diagrams and modification drawings. You will be given a detailed drawing brief or a request for change/modification order, and you will be required to access these requirements and extract all necessary information in order to carry out the drawing operations. You will need to select the appropriate equipment and drawing software to use, based on the type and complexity of the drawing functions to be carried out. You will be expected to use current British, European, International and company standards to produce a drawing template, for a range of paper sizes that must include the drawing title, scale used, date of drawing, material to be used and other relevant information. You will then be expected to produce fully detailed drawings to enable the manufacture, assembly, installation or modification of the product to take place.
Your responsibilities will require you to comply with organisational policy and procedures for working in the drawing office or CAD suite. You will be required to report any problems with the computer hardware, software or drawing procedures that you cannot personally resolve, or are outside your permitted authority, to the relevant people. You will be expected to work to verbal/written instructions and draught specifications, with a minimum of supervision, taking personal responsibility for your own actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work and will provide an informed approach to applying computer aided drawing procedures for mechanical engineering drawings. You will understand the computer system and software used, and its application, and will know about the various tools and techniques used to produce the drawings, in adequate depth to provide a sound basis for carrying out the activities to the required specification.
You will understand the safety precautions required when working with the computer drawing system. You will be required to demonstrate safe working practices throughout and will understand the responsibility you owe to yourself and others in the workplace.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety legislation and other relevant regulations, directives and guidelines
- prepare the system for operation and obtain data from relevant sources
- produce drawings that are sufficient and clearly detailed
- produce drawings in the required formats
- use codes and other references that follow the required conventions
- make sure that drawings are checked and approved within agreed timescales by authorised people
- ensure drawings are properly saved, registered and stored securely
- ensure that changes are completed as required by organisational procedures
Knowledge and Understanding
You need to know and understand:
- the specific safety precautions to be taken when working with computer systems (to include such items as safety guidance relating to the use of visual display unit (VDU) equipment and work station environment repetitive strain injury (RSI); the dangers of trailing leads and cables; how to spot faulty or dangerous electrical leads, plugs and connections)
- how to return the work area to a safe and useable condition (such as cleaning down work surfaces; putting mobile/social digital devices, manuals and unwanted items of equipment into safe storage; leaving the work area in a safe and tidy condition)
- the basic set-up and operation of the computer system, and the peripheral devices that are used (such as mouse, light pen, digitiser and tablet, printer or plotter, scanner, mobile devices)
- the correct start-up and shutdown procedures to be used for the computer system
- how to access the specific computer drawing software to be used, and the use of software manuals and related documents to aid efficient operation of the relevant drawing system
- how to deal with system problems (such as error messages received, peripherals which do not respond as expected, obvious faults with the equipment or connecting leads)
- the importance of protecting the computer system from viruses, and the implications if the correct procedure is not followed
- the documentation required for specified applications (such as drawing briefs, specification sheets, request for change orders)
- types of drawings that may be produced by the software (such as first and third angle drawings, sectional elevations, isometric or oblique drawings, assembly drawings)
- how to set up the viewing screen to show multiple views of the pattern to help with drawing creation (to include isometric front and side elevations)
- the national, international and organisational standards and conventions that are used for the drawings
- how to set up the drawing template parameters (such as layer properties, scale, paper size, colour set-up, line types, dimensioning system, dimensional styles, text styles, table styles, multi-leader styles)
- the application and use of drawing tools (such as for straight lines, arcs and circles, rectangles, polygons, ellipse; how to create hatching and shading on drawings; how to add dimensional styles and text styles to drawings, using the layer properties function)
- how to access, recognise and use a wide range of standard components and symbol libraries from the CAD equipment
- the need for document control (such as ensuring that completed drawings are approved, labelled and stored on a suitable storage medium, the need to create backup copies and to file them in a separate and safe location, filing and storing hard copies for use in production)
- the procedures for drawing change notes, trial changes, up-issuing of drawings, modifications, and miscellaneous amendments to drawings
- the sources and methods for obtaining the required technical information relevant to the drawing being produced (such as limits and fits, contraction allowances, bearing selection, surface finish)
- the basic principles of engineering manufacturing operations, assembly and installation methods, and limitations of the equipment/processes that are used to produce the drawn item (such as machining methods, joining processes, fabrication, casting and forging), and how these can influence the way you present the drawing
- the functionality of the component, and how it operates with other components and assemblies
- the extent of your own responsibility, and whom you should report to if you have problems that you cannot resolve when producing the drawings
Scope/range
| ** ** 1. Prepare the CAD system for operation, by carrying out all of the following: 1. check that all the equipment is correctly connected and is in a safe, tested and usable condition (cables undamaged, correctly connected, safely routed) 2. power up the equipment and activate the drawing software 3. set up the drawing system to be able to produce the drawing to the appropriate scale 4. set up and check that all peripheral devices are connected and correctly operating (such as keyboard, mouse, light pen, digitiser/tablet, scanner, printer, plotter) 5. set the drawing datum at a convenient point (where applicable) 6. set up drawing parameters to include layers, line types, colour, text styles, to company procedures or to suit the drawing produced 7. create a drawing template to the required standards, which includes all necessary detail 2. Use three of the following to obtain the necessary data to produce the required drawings: 1. drawing brief/request 2. specifications 3. change order/modification request 4. regulations 5. manuals 6. sample component 7. calculations 8. previous drawings/designs 9. sketches 10. standards reference documents (such as limits and fits, tapping drill charts) 11. notes from meetings/discussions 12. other available data 3. Take into account eight of the following design features, as appropriate to the drawing being produced: 1. function 2. materials 3. clearance 4. operating environment 5. quality 6. cost 7. aesthetics 8. standard parts/components 9. manufacturing method 10. lifetime of the product 11. physical space 12. safety 13. ergonomics 14. tolerances 15. interfaces 16. other design features 4. Carry out all of the following before producing the engineering drawing: 1. ensure that data and information is complete and accurate 2. review the data and information to identify the drawing requirements 3. recognise and deal with problems (information based and technical) 5. Interpret and produce drawings, using two of the following methods of projection: 1. first angle orthographic projections 2. isometric/oblique projections 3. third angle orthographic projections 6. Produce two of the following: 1. detail drawings 2. general arrangement drawings 3. sub-assembly drawings 4. assembly drawings 7. Produce mechanical drawings which include ten of the following: 1. straight lines 2. symbols and abbreviations 3. hidden detail 4. dimensions 5. curved/contour lines 6. sectional detail 7. angled lines 8. circles or ellipses 9. parts lists 10. text 11. geometrical tolerancing 12. insertion of standard components 13. other specific detail 8. Save, register, and store drawings in appropriate locations, to include carrying out all of the following: 1. ensure that your drawing has been checked and approved by the appropriate person/s 2. check that the drawing is correctly titled and referenced 3. save the drawing to an appropriate storage medium 4. create a separate backup copy and place it in safe storage 5. produce a hard copy printout of the drawing for file purposes (where required) 6. register and store the drawings in the appropriate company information system 7. where appropriate, record and store any changes to the drawings, and reasons for changes in the appropriate organisation information system 9. Produce drawings which comply with one of the following: 1. organisational guidelines 2. statutory regulations and codes of practice 3. CAD software standards 4. BS and ISO standards 5. other international standards |