Technological Preparation of Production and Work Design

Organization of the Production Function

The preparation of production is divided into two main, interconnected departments:

• Technological Preparation of Production (TPP): This department breaks down the technological process according to specific criteria to provide necessary information to the operational side. Ideally, technologists should collaborate during the design, development, and construction phases to ensure no significant changes are needed later due to technological constraints.

• Operational Preparation of Production (OPP): Focuses on the execution and scheduling based on TPP data.

The production function in a broader sense includes:

• Research & Development.

• Construction/Graphic Preparation.

• Work Preparation: TPP and OPP.

• Production: Manufacturing of parts and assembly.

• Quality Control: Product quality and manufacturing quality control.

• Auxiliary Activities: Toolroom and maintenance.

Tasks and Organization of TPP

The primary tasks of the Technological Preparation of Production include:

• Designing work and working conditions.

• Determining working times.

• Determining the technological process.

• Determining the component elements of the product (Material studies).

• Coordinating technological documentation.

Designing Work and Working Conditions

The purpose of work design within the production process is to:

• Minimize time and material losses: Aiming for the highest efficiency and speed.

• Reduce worker load: Minimizing physical and mental effort.

• Increase safety: Adhering to and improving safety at work.

• Contribute to quality: Ensuring results meet quality standards.

Fields of work design study include:

• Ergonomic workplace design.

• Motion study.

• Design and use of working tools and jigs.

Ergonomic Workplace Design and Anthropometry

Ergonomic design aims to prevent physical injuries, increase safety, reduce psychophysical loads, and improve the worker's attitude toward their tasks. It involves several sub-disciplines:

• Anthropometric workplace design: Using human body measurements.

• Physiological work design: Focuses on physical relief and reducing static work.

• Environmental design: Minimizing negative environmental impacts.

• Psychological design: Visual comfort and atmosphere.

• Information capture: Optimizing auditory, visual, and tactile signals.

• Organizational design: Managing shifts, rhythms, and breaks.

Anthropometry is the science of human body measurements and proportions.

• Static Anthropometry: Measuring body dimensions in a fixed position to design furniture, tools, and machines.

• Dynamic Anthropometry: Measuring dimensions while the worker is in motion during tasks.

Key Anthropometric Dimensions and Uses:

• Body Height: General informational nature.

• Eye Height: Location of the highest frequently used commands.

• Shoulder Height: Location of high-frequency commands.

• Elbow Height: Starting point for the height of the work surface.

• Lumbar Curve Height: Location of passive support for the lower back.

• Popliteal Height (Knee Height): Starting point for seat height.

• Maximum Reach: Location of highest commands and shelves.

Anthropometric Standards and Secular Trends: Standards must be updated frequently. Research by Bolstad, Benum, and Rokne (2001) showed that over 57 years, the average height of women increased by $33\,mm$ ($5.8\,mm/decade$) and men by $61\,mm$ ($10.5\,mm/decade$).

Postural Energy Consumption: The energy required for work is minimized when the posture is optimized:

• Seated Position: Uses $3-5\%$ effort; ideal for precision work.

• Standing Position: Uses $8-10\%$ effort; necessary for long movements or high force.

• Kneeling Position: Uses $30-40\%$ effort.

• Bent/Leaning Position: Uses $60-80\%$ effort.

Office Ergonomics and Seated Work

Regulations for safety and health when working with display screens (Slovenian Gazette No. 24735) specify:

• Work surfaces should be non-reflective with rounded edges.

• The seat surface should be textured/rough to prevent slipping.

• The seat should tilt back by $3^\circ$.

• Lumbar support must be provided.

• Seat tilt range: between $+5^\circ$ and $-15^\circ$.

Ideal values from the Office Ergonomics Calculator:

• Armrest Height: $73$ to $75$.

• Seat Height: $48$.

• Seat Pan Depth: $41$ to $48$.

• Monitor Height: $129$.

• Monitor Distance: $79$.

• Keyboard and Mouse Height: $73$.

Visual and Reach Zones:

• 20 degrees: Viewing without eye movement.

• 44 degrees: Viewing with eye movement, head stationary.

• 90 degrees: Viewing field if the head moves.

• Normal Reach Area: Movement of the forearm.

• Maximum Reach Area: Movement of the arm from the shoulder (Men: $80\,cm$, Women: $70\,cm$).

Environmental Factors (Impacts from the Surroundings)

Thermal Environment

The heat balance of the human body is expressed as: $S = M \pm C_1 \pm C_2 \pm R - E_v = 0$ Where:

• $M$: Heat from metabolism.

• $C_1$: Convection (heat flows).

• $C_2$: Conduction (transfer from warm to cold).

• $R$: Radiation.

• $E_v$: Evaporation (sweat).

Climatic units for measurement:

• Air temperature (dry and wet thermometers).

• Air humidity (hygrometer).

• Air movement (anemometer).

• Surface radiation temperature (globe thermometer).

Non-climatic factors:

• Metabolism: Energy consumption varies by activity (e.g., Sitting: $1.3\,kJ/min$; Running at 12 km/h: $47.9\,kJ/min$).

• Clothing Insulation: Measured in "clo." 1 clo allows $23\,kJ \times h^{-1}$ of heat per $1\,m^2$ at a $1^\circ C$ difference ($1.5\,clo$ for work clothes; $0.5\,clo$ for summer clothes).

Lighting

Measured in lux ($lx$) using light meters. Insufficient light or glare (sudden brightness) increases accidents and reduces quality.

• Standards (SIST EN 12464):

  • Warehouses: $30\,lx$.

  • Standard Workshops: $300\,lx$.

  • Quality Control: $600\,lx$.

  • Precision Work: $1000\,lx$.

  • Graphic Industry Color Control: $1500\,lx$.

Noise (Ropot)

Defined as disturbing sound. Measured in Decibels ($dB$) and frequency ($Hz$).

• Impact on Humans:

  • < 50\,dB: No obstruction.

  • $51 - 70\,dB$: Distracting/stressful depending on the individual.

  • $71 - 90\,dB$: Physical effects (constriction of blood vessels in limbs).

  • $91 - 120\,dB$: Long-term exposure causes permanent hearing damage.

  • > 121\,dB: Even short-term exposure causes hearing loss.

Vibrations

Measured by the $Kv$ factor (power of perception):

• $Kv = 0.1$: Hardly felt.

• $Kv = 0.25$: Distinctly felt.

• $Kv = 1.6$: Strongly felt.

Harmful Substances

Appear as gases, vapors, or aerosols (dust, smoke). Entry points include inhalation, skin penetration, or ingestion (poor hygiene). Protection includes technical, organizational, personal (PPE), and medical measures.

Psychological Work Design and Information Perception

Visual Comfort:

• Colors: Improve perception, reduce errors, and lower fatigue. Research suggests white walls should be avoided in schools; neutral shades (off-white, beige) aid eye relaxation.

• Plants: Improve atmosphere and sense of home.

• Music: Reduces worker talk, chases boredom. Mozart Effect: Mozart's music is said to reflect perfect symmetrical neural patterns, improving auditory and verbal skills. Vivaldi's "Spring": Suggested to stimulate mental abilities.

Information Capture:

• Auditory: Used for warning signals; don't require constant observation.

• Visual: Used for reading data. Carriers must be within an $80^\circ$ horizontal plane.

  • Standard reading distance: $300\,cm$.

  • Arabic numerals are highly recommended; Roman numerals are not recommended.

• Tactile: Used for switches operated by hand, foot, or fingers. Switches should be non-slip, clearly marked, and protected against accidental activation.

Organizational Work Design

Factors affecting daily performance include biorhythms, fatigue, breaks, and shifts.

Fatigue and Breaks:

• Types (according to Rohmert): Physical/biological, internal motivation, and workload-based.

• Breaks (ZDR Legislation): 30-minute daily break is mandatory (cannot be at the start/end of the day).

• Recovery: $75\%$ of energy is restored after 5 minutes; $18\%$ more after 10 minutes.

• Active Breaks: 7-12 minute exercise breaks during work can restore up to $70\%$ of working capacity.

Holiday/Leave:

• Minimum 4 weeks.

• Recovery research (Müller and Limmroth): 5 days to adapt to vacation; 14 days for physical/mental restoration; 2 days to readapt to work thoughts.

Shift Work: Negatively impacts biological, social, and health areas. Organization types include fixed, fast rotation, or slow rotation. Causes are technical, economic, or social.

Remote Work:

• Predicted to involve $70\%$ of the workforce at least 5 days/month by 2025. In 2023, EU remote work was at $22\%$.

• Pros: Flexibility, lower fixed costs.

• Cons: Isolation, burnout, distraction, motivation drops, lower socialization.

Motion Study and Systems of Predetermined Times (SVDČ)

Founders:

• Friederic Taylor: Scientific organization to increase productivity.

• Frank Gilbreth: Reduced bricklaying motions from 18 to 5. Defined Therbligs (18 types of motions like search, find, select, grasp, hold, etc.), assigning each a symbol and color.

Methods:

• MTM (Method Time Measurement): Developed by Maynard, Stegemerten, and Schwab in 1948.

• TMU (Time Measurement Unit): $1\,TMU = 0.0006\,min$ ($1\,min = 1667\,TMU$).

• Actions classified as: Reach (R), Move (M), Turn (T), Grasp (G), Release (RL), Position (P), Disengage (D), etc.

Advantages of SVDČ:

• High accuracy, objective results for average workers, eliminates the need for chronometer recording, allows for pre-calculations of costs and equipment needs.

Determination of Working Times and Norms

• Actual Time: Time actually used to perform a task.

• Norm (Normative Time): Time required by an average skilled worker under given conditions to work with normal effort without over-fatiguing.

Formulas: $T = T_{pz} + n \times N_{\check{c}}$ Where:

• $T$: Total time for a production order.

• $T_{pz}$: Preparatory-final time (setup/cleanup, counted once per batch).

• $n$: Number of pieces.

• $N_{\check{c}}$: Time norm per piece.

Norm Structure ($N_{\check{c}}$): Defined as $t_i + t_d$ (Manufacturing time + additional time).

• Manufacturing Time ($t_i$): Technological time ($t_t$) + auxiliary time ($t_p$).

• Coefficient of Additional Time ($K_d$): Usually $+15-20\%$; accounts for physiological needs, organizational losses, and machine maintenance.

• Coefficient of Effort ($K_n$): $+11\%$ for normal positions and loads < 50\,N.

• Coefficient of Environment ($K_o$): Typically $+10\%$ for extremely difficult surroundings.

Adjustment of Norms: Norm achievement $R$ is calculated as: $R = \frac{N_{\check{c}}}{E_{\check{c}}} \times 100$ Where $E_{\check{c}}$ is the effective hours used.

• R > 100\%: Norm exceeded.

• R < 100\%: Norm not achieved.

Production Process Planning

Planning aims to lower production costs by optimizing travel, control, and capacity use.

• Individual Production: For unique items; the worker defines specific operations based on a construction drawing.

• Series Production: Larger quantities; the worker gets instructions for specific operations; strictly normed.

• Mass Production: Broken down to individual motions; precise written instructions for workplace setup.

Process Presentation Methods:

• Descriptive: Using forms with task sequences.

• Visual (Hodogram): A spatial schematic showing the flow of materials/documents between workplaces.

• Graphic (Flowcharts): Using standard symbols:

  • Circle: Technological operation.

  • Square: Quality/quantity control.

  • Arrow: Transport.

  • Triangle: Planned storage.

  • D-shape: Planned delay/interruption.

• Modern Methods: 3D simulations and Virtual Reality (e.g., Audi e-tron GT digital planning).

Material Study and Value Analysis

Material Classification:

• Basic Material: Main component, standardized, high value, planned deterministically.

• Auxiliary Material: Required for manufacturing (e.g., chemicals) but not a direct component; low value, planned stochastically.

Material Norm: The specific quantity of material plus unavoidable waste required for one unit of product.

Value Analysis (VA): A method used to reduce material costs through four phases:

1. Gathering information (functions, costs, materials) via ABC analysis, etc.

2. Brainstorming for solutions.

3. Analyzing ideas to the level of operation.

4. Selecting the best ideas to implement.

Questions & Discussion

Interactive Poll Findings (via Mentimeter):

• What is important when working with a computer? Student answers included: Blue light glasses, good chair, clean environment, table height, literacy, focus/posture, mouse/keyboard quality, breaks, and screen brightness.

• Do you listen to music while studying? The discussion touched upon the "Mozart effect" and Vivaldi's "Spring" as tools for enhancing cognitive performance, though it was noted that research on intelligence increases remains unconfirmed due to small sample sizes.