TOM Additional Deck Flashcards
What are the wastes in TPS?
Transport - avoid as much movement as possible (co-locating parts of process)
Inventory - avoid as much as possible. better fast and little inventory than a lot and slow
Motion - avoid all excess movement that does not add value
Waiting - items should move at steady speed through the system ‘not touching the floor’
Overproduction - only do things when they need to be done
Overprocessing - don’t make something more complicated than it needs to be (e.g. IT)
Defects - if something is done wrong, fix instantly, otherwise there will be followon defects
Skills - use whoever is qualified, not overqualified
What is lean production (TPS) trying to achieve? (3 things)
Eliminate waste (muda) Reduce unevenness (mura) Reduce overburden (muri)
Define efficiency and example measures
How well a process turns inputs into outputs
E.g. labour, machine, material, energy utilization
Define effectiveness
How well a process delivers promises to customers - quality, speed
Which are the types of quality in effectiveness
Performance quality - delivers a high level of performance on set dimensions (e.g. luxury hotel)
Conformance quality - how well a product delivers in its specifications (e.g. budget hotel)
(speed is part of effectiveness measurement together with Speed)
Measures for speed
AVG TPT (Throughput)
Minimum TPT
Leadtime
(both part of effectiveness measurement together with quality)
What are the different process types? Plus examples
Product focused operation (e.g. worker paced lines, machine paced lines, continuous flow process)
Process focused operation (e.g. job shop, machine shop)
All order fulfillment strategies (4)
Make-to-stock
Assemble-to-order
Build-to-order
Engineer-to-order
Types of inventory (4)
RAW materials
WIP
Finished goods
Safety and cycle stock
MRP Inputs
Master production schedule (MPS)
Bill of materials (BOM)
Inventory master file
MRP Outputs
Work orders
Purchase orders
Rescheduling notices
Significance / advantages of JIT system (3)
Weaknesses of JIT (2)
Adv: Prevents overproduction
Limits total WIP inventory to production authorized by Kanban (pull system)
Beats MRP system (push system) on lead time and inventory levels
Weak: schedule variability needs to be kept below 5-10% around planned levels
System is tightly controlled and unable to cope with large swings in volume or product mix
Process improvement techniques
Performance measures (e.g. QCD -quality cost delivery, efficiency, effectiveness) Process improvement (e.g. Kaizen, Deming Cycle) Root cause analysis (e.g. 5why, Pareto analysis)
4 concepts of SPC and what can it be used for
Common cause variation
Assigned cause variation
Control - process only exhibits common cause variation = stable or in control. Assignable variation = out of control
Capability - it consistently meets design and/or customer specifications
Can be used for repetitive, measurable and quantifiable processes.
Definition JIT
A pull system of providing processes in the assembly line with only the items that they need when they need them.
Primary objectives are:
- save warehouse space
- improve efficiency
How to apply efficiently: rely on ordering signals from kanban boards
Definition Jidoka
Jidoka means automation with human intelligence.
Mechanical Jidoka: design equipment to stop automatically and to detect problems when they occur
Human Jidoka: in TPS, operators may pull andon if they notice something suspicious
Goals is to prevent producing a series of defectives items
Definition Heijunka
Heijunka is a Japanese word that means „leveling“ - when implemented correctly it helps organizations to reduce waste while meeting demand.
Definition Bullwhip effect
Plus its 5 causes
A supply chain phenomenon in which orders amplify as they move along a supply chain.
- Demand forecasting and signal processing
- Lead times
- Batching (Burbridge effect)
- Price fluctuations and promotions
- Rationing and inflated orders (Holihan / flywheel effect)
Information sharing - 3 types
EPOS - Electronic POS Data
CF - collaborative forecasting
Sales promotions
Supply chain risk management (3)
- Location pooling (put together stock from multiple territories = less risk of stock out)
- Product pooling or postponement (modular design which can serve overall demand)
- Capacity pooling (each production facility can produce several models to counter peaks / dips for individual models)
IDEF0 diagram
Middle transportation process, arrows:
Top ‘control’
bottom ‘resources or mechanism’
left ‘input’, right ‘output’
Little’s Law
Work-in-Process = output rate * throughput time
(output rate = production rate;
throughput time = lead time)
Types of Quality (general)
Product Quality = how it’s experienced by the customer
Process Quality = how many mistakes get made when a product or service is being delivered
Different types of errors in processes / what can be done wrong in assessing a process
Type 1 error = reject something that is good
Type 2 error = not reject something that is not good
Different types of variation
Common cause variation = ‘normal’
Special Cause Variation = in principle should be avoided
Kaizen
Principle in the management of quality to seek continual improvement in small steps from people who do the work.
Product Process Matrix x and y axis
Y-axis variety, x-axis volume
Deming cycle (PDCA)
plan, do, check, act –> continuous improvement (circle, from top left clockwise)
Symptoms of process failure
Workarounds
Poor morale
Staff turnover
run ratio
percentage of items made right in the first place
Andon - what happens when pulled
Yellow board with number of production station = notifies supervisor of problem, red = stopped, also notifies whether a process is starved or blocked
5S
Sort Set in Order Shine / Sweeping Standardize Sustain
5s is a workplace organisation method (japanese) for effectiveness and efficiency
Six Sigma Process
A process is a six sigma process if it exhibits no more than 3.4 defects per million (+- 6 standard dev)
Three elements of effective project management
- Cultivating, creating and selecting the right portfolio of projects (doing the right things)
- Executing projects quickly and efficiently (doing things right)
- Learning from project experience (doing it better over time)
Additive Manufacturing
Is a class of manufacturing technologies that allows to build a material layer by layer (now) - potentially more dimensions in future.
Scrum key facts
Scrum is a framework for managing work (with an emphasis on software development)
- break work into small actions that can be completed within timeboxed iterations (sprints, typically 2 weeks)
- track progress and re-plan in 15-minute stand-up meetings, called ‘daily scrums’ (PDCA similar structure)
Scrum roles: Product owner (represents customers, makes sure projects deliver business value), development team, scrum master (ensures scrum process is followed)
3 steps to make process mapping work
- Go to workplace (gemba), speak with key actors
- Capture the vital few (only what is needed)
- Stick to mapping methodology
2 different types to respond to customer demand
pull scheduling - produce what is needed only when it’s needed, customer triggers order (working backwards from there to produce just in time)
push scheduling - production is driven by a central schedule (that is often based on forecast demand) that triggers production and material is pushed from one stage to the next, according to this central schedule
MRP definition
MRP stands for ‘Material Requirements Planning’ and refers to a computer system that calculates the exact requirements of components and materials for a given end product, or more accurately, for a complete schedule of products (the so-called Master Production Schedule).
MRP classifies as a ‘push’ system.
MRP weaknesses
(1) MRP (a push system) systems work on fixed batches and fixed lead-times. Combined, these two aspects tend to lengthen lead-times, and in turn, increase WIP levels. MRP on avg. hold more WIP inventory than JIT (a pull system).
(2) MRP systems plan on end item level, and thus do not synchronise between items that may be sharing parts. This was found to cause uneven orders for suppliers, which in turn can trigger dynamic distortions in the supply chain (‘bullwhip effect’).
2 types of kanban commonly used
Type 1: A withdrawal kanban that allows for material to be removed from the kanban supermarket, for it to be sent to the process that needs it.
Type 2: A production Kanban that allows a process to produce a replenishment batch once inventory is withdrawn from the kanban supermarket.
The Three Golden Rules of Forecasting are:
(1) The forecast is always wrong.
(2) The longer the forecast horizon, the worse the forecast becomes.
(3) The less aggregated, the worse the forecast becomes.
Statistical Process Control
Statistical process control (SPC) is a method of quality control which employs statistical methods to monitor and control a process. This helps ensure the process operates efficiently, producing more specification-conforming product with less waste. SPC can be applied to any process where the “conforming product” (product meeting specifications) output can be measured.
Statistical Process Control is mostly concerned with the chosen variable’s mean (the process mean) and variability.
Mean chart
Also known as an (x-bar) chart, the mean chart captures averages from a series of samples. It is a sequential (time-ordered) plot of the sample means.
(e.g. 25 samples a 5, avg of 5 is displayed in chart)
Neither chart on its own is sufficient to say if a process is in control.
Range chart
Like standard deviation, the range of a sample is a measure of its dispersion around the mean—that is, a measure of its variability.
(e.g. 25 samples a 5, range = max-min of sample of 5)
Suspicious patterns range / mean charts
- Ten or more consecutive points are either all above or all below the chart’s center line.
- A series of points show an upward or a downward trend.
Fishbone / cause and effect diagram
Materials, Person, Method, Machines, Problem (end arrow)
Iron triangle
The quality of work (middle) is constrained by the project’s budget, deadlines and scope (features).
The project manager can trade between constraints. Changes in one constraint necessitate changes in others to compensate or quality will suffer.
3 types of uncertainty that can impact any process / factory in a supply chain
- Demand uncertainty
- Conversion or throughput uncertainty
- Supply uncertainty
(4. Actual (= customer) and self-cretaed uncertainty)
Collaborative Planning, Forecasting and Replenishment (CPFR)
The collaborative planning, forecasting and replenishment approach (CPFR) was developed by the grocery retail sector (see vics.org), and effectively merges the VMI and collaborative planning elements, to form a model of close supply chain collaboration.
The 3 T’s of Highly Effective Supply Chains
Time, Transparency, Trust
4 V’s of Toyota
- Variety: Determine your variety of offerings based on operational efficiency and market demand
- Velocity: Maintain a steady flow through all processes of the supply chain
- Variability: Manage inconsistencies carefully to reduce cost and improve quality
- Visibility: Ensure the transparency of all processes to enable continuous learning and improvement
Triple A supply chain
- Agility to respond to changing customer needs
- Adaptability to long-term changes in markets and technology
- Alignment of incentives to enable cooperation and coordination across tiers in the chain
Limits of 3D printing / additive manufacturing
- currently economically unfeasible for printing a vast majority of parts - when customisation is not important, 3D printing is not economically attractive
- considerable pre- and post-processing, which incur non-trivial labor costs (file conversion, post-processing, e.g. sanding)
Sand Cone Model
Sand cone model suggests that although in the short term it is possible to trade off capabilities against each other, there is actually a hierarchy amongst the four:
- Cost efficiency
- Speed
- Dependability
- Quality (bottom of pyramid, start here, when accomplished, focus on the next)
Main objective of Supply Chain Management (SCM)
SCM seeks to achieve stable and reliable flows in the system.
Ways to mitigate supply chain distortion
VMI
Information sharing - EPOS and CF, sales promotions
CPFR (Collaborative Planning, Forecasting and Replenishment)
Process types
Process focused (Job shop, flexible, less efficient) Product focused (by flexibility / volume): worker-paced (batch, single piece flow), machine-paced line, continuous flow process
Push-pull envelope
Combination of push & pull (forecast push at the same time with customer pull, e.g. restaurants, use as complements
Production Planning and Control (PPC) - Definition / Purpose
The purpose of production planning and control (PPC) is to provide
- the right products
- in the right quantity
- and quality
- at the right time
- and place
– while minimising operational expense in production.
Forecasting Methods
Qualitative (e.g. assumptions from market surveys)
Quantitative
- extrinsic (based on factors outside firm level)
- intrinsic (based on patterns in data at firm level)
Kaikaku or ‘kaizen-blitz’
focussed local improvement action (rapid and fundamental change)
SMED (single minute exchange of dies)
A lean production method for reducing waste in manufacturing. It provides a rapid and efficient way of converting a manufacturing process from running the current product to running the next product. This rapid changeover is key to reducing production lot sizes and thereby improving flow (Mura), reducing production loss and output variability
Nemawashi
Nemawashi (japanese, ‘going around the roots’) means an informal process of quietly laying the foundation for some proposed change or project, by talking to the people concerned, gathering support and feedback, and so forth. It is considered an important element in any major change, before any formal steps are taken, and successful nemawashi enables changes to be carried out with the consent of all sides.
Agile
Agile software development (rapid application development RAD) describes a set of values and principles for software development under which requirements and solutions evolve through the collaborative effort of self-organising cross-functional teams. It advocates adaptive planning, evolutionary development, early delivery, and continuous improvement, and it encourages rapid and flexible response to change.
Principles:
Individuals and Interactions over processes and tools
Working Software over comprehensive documentation
Customer Collaboration over contract negotiation
Responding to Change over following a plan
90/10 rule
90/10 rule: use 90% of machine time for production, 10% for setup and maintenance
Poka-Yoke
Poka-Yoke (English: Mistake-proofing): Failsafe devices in the production process (sensors, templates etc) that automatically stop the line when an abnormality occurs.
Kingman’s Formula
used for queues with one server
E(Wq) = (p/(1-p)) * (Ca^2 + Cs^2)/2 *r
r = mean service time p = utilisation Ca = Coefficient of variation for arrivals Cs = Coefficient of variation for service times
Why is inventory expensive?
- ties up working capital
- takes up space
- gets lost or stolen
- gets dirty and breaks
- becomes obsolete
- goes off its expiry date
- needs handling
- needs managing
Purpose of process mapping
Process mapping is supposed to help understand 3 things
1 What the actual process looks like
2 What the main stages or steps are
3 Who the main stakeholders are
Definition workaround
A workaround is a bypass of a recognized problem in the system. Usually this would be a temporary fix implying that a genuine solution fixing the underlying cause of the bypassed problem is needed
Definition project
A project is a temporary undertaking to produce a pre-defined objective, under certain constraints, e.g. budget, time, labour, legal, etc.
Process walk
Process walk is when a series of points show an upward or downward trend - thus the process is slowly shifting or ‘walking’. Even if points are within the customer specs it is important to investigate as it is unlikely to be due to random variation but likely has a specific cause. If left alone the process could quickly no longer be capable. Process walk could be due to various reasons such as a shift in process input parameters or a fault with machinery.
3 types of buffers in manufacturing
1 Inventory buffer such as holding safety stock gives you a buffer for situations where
there is delays in receiving stock from vendors, delay in ordering stock etc.
2 Capacity buffer is having spare capacity in the system for emergency situations - for example having access to extra machines if at capacity
3 Time buffer refers to building enough spare time in process to account for anytime delays throughout the process. The promised delivery date to customer could be set for a period of time after when products are expected to be ready
things to add in SPC chart
x-axis process outcome y-axis n mean LCL, UCL LSL, USL
Strategic Framework for effective project management
- Seeding
- Weeding and Feeding
- Cultivating
- Plowing under
