Upload
apollo
View
52
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Production schedule for a automotive motor head manufacturing plant. Anirudh Jagannathan aj2560 Jorge Ortiz jeo2130 Yanira Pichardo yp2323. Problem description. The plant we will be studying is Nemak’s Plant #4 in their Monterrey site, focusing on their core blowing operation. - PowerPoint PPT Presentation
Citation preview
Production schedule for a automotive motor head
manufacturing plantAnirudh Jagannathan aj2560
Jorge Ortiz jeo2130Yanira Pichardo yp2323
Problem description
The plant we will be studying is Nemak’s Plant #4 in their Monterrey site, focusing on their core blowing operation.
A consultancy project took place back in 2010, with one of the deliverables being an Excel workbook with macros that automated the creation of each week’s production schedule.
The production schedule workbook delivered back then was done in such a way as to try and meet the production deadlines as much and as well as possible(ƩLmax) and try and make each machine finish around the same time, having the minimum amount of downtime as possible (ƩCmax).
Process diagram
Milling Core blowing
Motor head
moldingCleaning De-
burring
Packaging for
shipping
Sand Resin Aluminum
Core assembly
Destroyed cores
Excess aluminum
Motor head
Project objective
We want to determine the following:1. Was the production schedule proposed back in 2010
optimal or not (ƩCmax, ƩLmax) 2. How we could improve it. 3. How far from optimal was it.
Stretch goal1. Figure out if the way the Excel macro was programmed
(running time) was efficient or not, going into Big O notation.
Problem complexity
1. The plant has 21 core blower machines. 2. Production requirements for the following week arrive each
Thursday morning and are detailed on a daily basis (daily due dates).
3. Plant managers can set priorities to each product that is in the production requirements for the week. (weights for each job)
4. Each core blower can blow certain types of cores for each product.
5. Each core blower can work with only a certain set of toolings.
6. Each product is made up of multiple cores and there are cores that form part of more than one type of product.
7. We have information regarding core blower machines and tooling availabilities for each week (sometimes either machines or tooling are undergoing preventive or corrective maintenance).
8. We have information regarding the current state of the inventory and in some cases, for some products, there is a “produce up to level”.
General macro logic1. Daily turntable requirements2. Product prioritization3. Machine availability4. Tooling availability5. Initial inventory (automatically pulled by the
macro)6. Build of materials for each product
1. Sort the products using the prioritization list.2. Consult the product’s build of materials.3. Consult the initial inventory.4. Determine if the core being analyzed is in stock or it has to be
produced.5. If the product has to be produced, allocate an available tooling.6. Allocate to the first available machine that is compatible with this
tooling.7. Go to the next core of that product until you finish its build of
materials.8. Go to the next product down the prioritization list until you finish
with the whole requirements list, or you run out of available machine-hours in the day.1. Detailed production schedule
2. Summarized production schedule
3. Graphs
INPU
TSPR
OCE
SSO
UTP
UTS
Current scheduling
The way that the macro programs the schedule is by following a slight variation of the McNaughton’s wrap-around rule.
It’s a variation because the schedule length rule isn’t necessarily followed:
In the case that is larger than the available hours in the day, our schedule’s makespan is indeed the day’s available working hours, and the daily demand for that product will not be met.
Current scheduling
Current scheduling
By using the wrap-around rule there’s risk that if a machine breakdown occurs (specially late during the day), you might be unable to fulfill your orders because you are missing one or more of the cores required to assemble a specific product.
J 2
J 3
J 3
J 2
t=Dt=0
J 1M1
M2
M3
Proposed scheduling
By using an alternative scheduling algorithm, where a job is assigned to each machine and once all machines have a job assigned to them you assign a second job and so on, you can reduce the aforementioned risk, reduce the makespan, and balance your operations (little or no idle time in machines).
J 2
J 3
t=Dt=0
J 1M1
M2
M3
t’=D’
Proposed scheduling
Proposed scheduling algorithm
Order the products by priority. For each product in the priority order,
Calculate , where n is the number of core parts to be produced and t is number of tools available for the core type. Ratio tells us how many parts each tool will work on (as parallel processing is allowed).
Sort the core types in decreasing order of (similar to LPT rule for P||Cmax)
For each core type, we allocate machines (until we run out of available machines or available tools) and schedule the blow operations.
Once all parts of a given core type are completed on a machine, identify next core operation in order of product + core priority and redo the previous step.