Equipment Focused Methods Flashcards
Why do we need methods for avoiding waste?
To get high productivity of resources (equipments and people) and adhere to the business plan where paybacks of investments are expected.
However: paybacks are not guaranteed. Thus, weak points must be identified.
What are the two methods used in order to determine equipment weak spots?
Equipment Focused Methods and Human Focused Methods
What is the purpose of Equipment Focused Methods? What are some methods of optimization?
To maximize the operational effectiveness of an equipment
Methods for optimization: Implementation of TPM Low cost automation SWCT ECTS Standard Principles Body in White & LCC Flexible work system
What is the purpose of Human Focused Methods?
To maximize the operational efficiency of people
What are the two possible steps in the Equipment Based Process?
Planning or redesign
Equipment based processes are being improved in terms of effectiveness in the planning phase of a new design as well as in reengineering in the context of TOS projects & activities.
What is a New Design and what does it entail?
TOS Implementation of new processes
- Planning based on standards principles
- Application of Lean Conformity Check
- Station development workshop to check and confirm planning state
What are the steps when approaching a redesign of a bottleneck in a process?
- Value stream mapping and bottleneck identification
- Detailed analysis on the bottleneck
- Definition and implementation of countermeasures
- Stabilization of implementations
Value stream (analysis) in the equipment focused method is?
The basis of any equipment optimization
–a standard method for visualizing the entire process of a production including lead time as well as connection of material and information flow
–the visualization of waste and its sources in the overall process
–a common language when talking about the manufacturing process
–an objectification of the discussion about the necessary optimization through numbers, data and facts
What are the steps of the Value Stream Process in Equipment Optimization Projects?
- Determine customer demands
- Draw process steps
- Collect process data
- Collect inventory data
- Determine external material flow
- Draw internal material and information flows
- Calculate throughput time and enter value creation time
- Weak points/findings out VSM analysis
IT-tools support the creation of VSM
Interactive tool based on Excel for equipment:
- -Illustration of VSM
- -Cycletime of all equipment in overall process
- -Trend of downtimes
- -CT-Downtime Matrix
IT based solutions available:
–e.g. value stream modeler (www.ifakt.de)
Keep an eye out for this tool as well:
–MPS App (by Siemens)
In context to equipment related processes, takt time is the basis for what?
- Deriving capacity by consideration of given processing time
- Balancing workload in automatized system to avoid bottlenecks
- Output management to see deviations in processing time from takt time
Equipment Cycle Time is the sum of?
the sum out of primary (productive time) and secondary (part change time, positioning time, tool change time) processing time
What happens in the primary equipment processing time?
a productive process is happening (parts are being machined).
The secondary equipment processing time is a compound of which three “times”?
- part change time: the time that is needed to change parts on the machine
- positioning time: the time that is needed to reposition the machine or parts of the machine
- tool change time: the time that is needed to change a tool at the machine
What is the Theory of Constraints?
- Every system has only one bottleneck at any one time
- The capacity of the system is determined by the bottleneck
- Optimization at a non-bottleneck is not purposeful and therefore waste
The equipment capacity (production volume) is limited which three dimensions of losses?
- Usage- measurement is reduction
- - Unoccupied shifts
- - Breaks & maintenance - Effectiveness- measurement is reduction
- -Maintenance & technical downtime
- -Setting up
- -Idle time (Start-up / runout losses)
- -Cycle time losses
- -Rejects
- -Re-work - Machine cycle time- measurement is optimization
- - Primary processing time
- - Secondary processing time
Which of the following is not an equipment dimension of losses? Line takt Usage Cycle Time Effectiveness
Line takt
The identification of the bottleneck depends on
whether the line is a simple line or a complex line
As opposed to a complex line, what is a Simple line?
- The interactions between machines are clear
- The complexity of machining is manageable
- Machines are not interlinked or only rigidly linked
- Operation oriented or standalone machining island
Bottleneck identification is based on: Expert opinion (balance between production, planning and maintenance)
What does a Complex line mean?
- The interactions between machines are complex
- Flexible interlinked line, automated, with (dynamic) buffers, serial or parallel
Bottleneck identification is based on:
Simulation
OEE Monitor (based on Prisma data)
If the bottleneck is not clearly visible, what is required?
detailed analyses are required
The interlink between equipment influences the dynamic, and thus output of the overall system
What is a Rigid Interlink?
Rigid interlink= lifting bar
The Line Output Takt is calculable
It is determined by:
- the machine with the longest cycle time
- the line availability, the product of all individual availabilities
Line Availability: Aline = AOP10 x AOP20 x … x AOPn
Line Output Takt: Taktline - CTbottleneck / Aline
What is an Elastic Interlink?
Elastic interlink= conveyer
Line Output Takt is not calculable.
It is determined by:
- -the machine with the longest cycle time
- -the line availability, which is not calculable
Line Output Takt: determinable through simulation
What is Slack interlink?
Slack interlink=storage
The Line Output Takt is calculable.
It is determined by:
– the machine with longest average Output Takt
Output Takt by OP: TaktOPn= CTOPn / AOPn
Line Output Takt: Taktline = max(TaktOPn)
To identify a system‘s bottleneck, there are 3 proven methods available, depending on the system used. What are they?
- Cycle time/machine downtime matrix (static)
- Change-point-method (dynamic)
- Active period method (dynamic)
Cycle time/machine downtime matrix (static)
- The machine with the longest Output Takt is the bottleneck
- Low demands on input data; possible to write out by hand or use of PDA eg. PRISMA
- Not accurate with an elastic interlink, as there is no consideration for the dynamic in the system
Apply to rigid interlink and slack interlink
What is the Change-point-method (dynamic) with reference to bottlenecks?
- The machine whose status changes from more output blocked to more input empty (starved) is the bottleneck
- Reporting of logistical downtimes (starved, blocked), possible to write out by hand or use of PDA eg. PRISMA
- Intuitive and easy to understand
- No explicit predication
Apply to elastic interlink
What is the Active period method (dynamic)?
- Most reliable and most advanced method
- Machine with the longest mean active time is the Bottleneck
- Inactive time: Logistical conditions
- Active time: All other conditions such as automatic, malfunction, manual operation, etc…
- Machine with the longest mean active time is the Bottleneck
- Higher demand on data quality, namely data from PDA
Apply to elastic interlink
In reference to bottlenecks what does a Value Stream Analysis do?
In the context of the value stream analysis showing the stocks between the individual plants.
The bottleneck is the plant in front of which the workpiece stocks are highest.
Advantages:
easy data collection
Disadvantages:
Accuracy is guaranteed only if the buffer size is unlimited, otherwise there is no clear bottleneck determination
When referring to bottlenecks, what is the Change Point Method?
The inflection point method displays the sum of the logistical states “blocked” and “waiting” per system.
Bottleneck is the plant where a turn from “blocked” to “waiting” takes place and the sum of logistical downtime is lower than at the surrounding stations.
Advantages:
Consideration of the chaining
Disadvantages:
no statement about the other loss factors
several bottlenecks possible
Apply to elastic interlink- conveyor
Cycle time – Equipment Effectivness Matrix (CT-EE)- Bottleneck
Comparison of system failures (technical faults) and associated cycle times of each individual system. Possible bottlenecks are plants with the highest cycle time and/or low plant effectiveness (for linked systems, the logistical disruptions are taken out of the system).
Advantages:
quick identification of possible bottleneck machines and their loss factors
several bottlenecks possible
Disadvantage:
ignores the chaining and material flow
When determining a bottleneck, what is an Active Period Method?
The bottleneck is the station with the longest average active duration.
“Active” states can put other systems into a waiting state (machining, fault, repair, tool change, set-up). “Inactive” states are all waiting states of a system (blocked, waiting).
Advantage:
Consideration of all loss factors and the links
Disadvantage:
several bottlenecks possible
What is active machine condition?
operating
repairing
Incident/breakdown
manual mode (change over, tool change/replacement, maintenance, etc.)
Inactive machine condition
waiting for parts (starved)
blocked (e.g. machine in front is down)
According to the Active Period Model, in a system with interlinked machines the bottleneck is…
the machine with the longest mean active time in the interval investigated:
- -consideration of all loss factors of the machines including interlink
- -multiple bottlenecks possible if mean active time shows no clear difference
- -Not applicable at slack/manual interlinks (machines are feeded manual)
Prerequisite is availability of data from all machines which are in scope by production data acquisition (e.g. PRISMA) and high quality of data.
Sources to get data from machine conditions
Production Data Acquisition (PDA) and Manual Records
Production Data Acquisition (PDA)
- Use of automatic generated data from equipment e.g. WEB PRISMA
- Equipment conditions are recorded with the time new conditions occur
- Bases for Shopfloor Management and problem solving
Important:
- -Maintenance of data base (e.g. target cycle time ..) and operating calendar
- -Before usage of data a detailed validation of data and machine conditions is required – “is my measuring system capable?”
- If no valid data from a PDA is available, manual records about machine conditions need to be carried out
Manual records (24h Analysis)
- If no data from a production data acquisition system are available or not reliable, manual records of the machine conditions are required
- Equipment needs to be observed in operation for a defined time
- Records of machine conditions can be taken directly in a EXCEL to minimize effort for analysis
- Manual records are time consuming and need detailed preparation and guidance of observers
Overall Equipment Effectiveness (OEE)
Overall equipment effectiveness (OEE) provides a view of the effectively used capacity of the machine or equipment for added-value activities based on the entire time available (365 days, 24 hrs. = plant operating time).
Application:
Evaluation of output capacity
Deriving measures for increase of utilization e.g. additional shift, production during breaks…
Long-term investigations
*includes planned losses