Posts Tagged ‘Constraint Management’

Elevate the Constraint

Monday, July 12th, 2010

elevate

To elevate a constraint is to make it the number one priority and work on increasing its capacity. Although we have talked bits and pieces of this step in several of the other steps, here we focus on just the constraint. So here are a few ways to elevate the constraint.

  • Add capacity to the constraint. This means adding people and/or equipment. The equipment you add does not have to be new or the same equipment you are currently using, it just has to do the same job even if it runs at a slower rate. This added equipment or personnel  increases capacity.
  • Adjust flow to match constraint. We have mentioned this before and restate it now. What this does is decrease inventory and confusion all over the area. It also makes everyone up and down stream from the constraint aware of the constraints rate (beat of process) and thus the importance of keeping it running.
  • Decouple operations if data verifies this can be done. Some things can be done on products that do not go through the constraint. Other things can be done at the same time (in parallel)  and later coupled up with items going through the constraint.
  • Implement a flexible work cell. A flexible work cell is an work area that can be easily changed or adapted to do several tasks. This goes along with the decoupling. While an operation is waiting on the constraint (one of the seven types of waste),  have it quickly change and do a different task that needs to be done that is not part of the constraints process flow line.
  • Eliminate any non-value added tasks being performed at the constraint. Create a process flow map of the steps that are performed just at the constraint and identify the value added steps and the non value added steps. Totally eliminate the non value added steps or at least remove those tasks from the person working the constraint. Think of the surgeon again, with all the help in the room the surgeon is doing all the value added task while all the help is doing what is considered non value added tasks. These task are now being done in parallel (Decoupled from the flow).
  • Reduce parts handling. Look at the constraint and try to do as much as you can at one holding of an item. Take an item, do what is needed without releasing it and pass it on. If you have to keep turning it over or reloading the item it just adds time and opportunities to create a defect in it.
  • Reduce waiting or storage. Here we want to insure that at the constraint is NEVER waiting for anything. Plus nothing is waiting at the constraint to be used. Now that is near impossible but we want to reduce both of those as much as possible.
  • Reduce or eliminate the process variation. One easy way to do this is by implementing error proofing. Error proofing is a way that when putting two things together there is only one way it can be done. On a form, check boxes are a way of error proofing.
  • Reduce setup at the constraint. Setup is a non value added task and if you can eliminate, reduce or decouple setup you should. Sometimes setup can be done at a step in the process while the step is working. Again look at a surgery room. While the doctor is removing the patients heart, we should be preparing the transplant heart (setup) to be ready for immediate installation. In the pit at the race track, the pit crew does not wait until the car comes in to get the materials that are needed. They have everything laid out ready for the car as soon as it comes in. All this setup is done done while the process (car) is running (still on the track).
  • Reduce Waste – There are seven basic types of wastes that I have talked about in another article. They are: Corrections, Overproduction, Movement of material or information, Motion of employees, Waiting, Inventory, and Processes.  One of the best tools to reducing these wastes is the 5S’s: Sort, Simplify, Sweep, Standardize, and Sustain. Reducing these can save you time and money.

Well there you have how to elevate a constraint in your process. The last of the five steps in constraint management is to go back to step one; Identify the constraint. The reason you start again at step one is that if you have improved the constraint it probably is no longer a constraint and some other step has become the constraint. You continue to do this until the process has no constraints. In other words until the rate of the process exceeds the demand placed on it. You may, in fact, have a slow step but if you still meet demands it is just that; a slow step and not the constraint. If, you have questions or comments please feel free to contact me by leaving a comment below, emailing me, calling me, or leaving a comment on my website.


Bersbach Consulting
Peter Bersbach
Six Sigma Master Black Belt
http://sixsigmatrainingconsulting.com
peter@bersbach.com
1.520.829.0090

3rd Step – Subordinate all other Tasks to the Constraint

Thursday, June 24th, 2010

surgeon

In constraint management after you have identified and exploited the constraint, you must subordinate all other tasks to the constraint. If you do not do this all you will have is people wasting time and materials creating parts of a completed product that no one wants. Then you have to spend money keeping track of all the excess inventory until you can use it. It is better to move those resources to helping the constraint task complete its works as quickly as possible. Think of your constraint as the surgeon of the process. All other tasks being performed in the operating room are subordinated to the surgeons work. Materials and tasks are brought in for use right when the surgeon needs them. Here are some helpful hint about subordination.

  1. You can decrease the output of all the rest of the tasks in the constraints process. Tasks before the constraint, will just build up inventory that cost you money. Money tied up in materials and labor to create the inventory that is sitting waiting for processing at the constraint. While it seats you have to keep track of it and store it until you use it. This also happens at tasks after the constraint. Here processes build inventory that sits waiting for the constraints task to be completed before they can complete their task.
  2. Since the capacity of the other tasks is larger than the constraint you can cut back on the utilization of the resources at those task and even move them to help the constraint. Sometimes these resources may not be as efficient as what is at the constraint but every little bit of output at the constraint helps.
  3. Increase the time that the constraint is being run. If the constraint task is only being done Monday through Friday from 8 – 5, then add the weekends or shifts for the constraint, This will increase the overall output of the process.
  4. Make sure that everyone know what the constraint is and what is needed at the constraint to keep it working. Put the information in every tasks written procedures. This way everyone will know the importance of keeping the constraint running and will make it their job to see it is working full time.
  5. Put in place a way to monitor the constraint so everyone know how it is doing at all times. Monitor Constraints throughput and/ or buffer sizes. Information is a great thing when everyone know what is happening and what is important.


Well there you have how to subordinate all the other tasks to the constraint in your processes. Next time I will address how we elevate a constraint. The forth of five steps in constraint management. As always if, you have questions or comments please feel free to contact me by leaving a comment below, emailing me, calling me, or leaving a comment on my website.


Bersbach Consulting
Peter Bersbach
Six Sigma Master Black Belt
http://sixsigmatrainingconsulting.com
peter@bersbach.com
1.520.829.0090


Exploiting the Process Constraint

Thursday, June 3rd, 2010

Exploit ConstraintOnce you have identified your constraints, the next step in constraint management is to exploit them. This mean to utilize them to their maximum extent. To exploit the constraint we have to take a look at a few things first.

  1. We need to look at the existing work in process (WIP) and throughput levels and compare them to the goals or proposed levels or TAKT time for the constraint.
  2. We need to look at the line flow requirements and compare it to the constraint capacity.

These two will give you a feel for how bad things are. Look closely at these comparisons and them do the following things:

  1. Develop a layout depicting buffer locations and sizes. Remember that buffers are one of the Seven Types of Wastes so try to maintain them as low as possible, but never let the constraint run out of raw materials to perform its tasks.
  2. Determine equipment needs. Here we look at if we can find other equipment to help the constraint move product faster. This may include buying more of the same equipment and creating another parallel operation to increase product flow to meet the demand.
  3. Once you have the first two done then adjust the process flow rate to match the capacity of the constraint. This will reduce materials from piling up at the constraint and making thing confusing.
  4. Rebalance operations. Not all products you produce require all operations in the process so something may bypass the constraint or can have other thing performed on it before it needs to go through the constraint. Ignore local efficiencies. Building more products at other operations just to keep people busy does not increase sales it only increases expenses.
  5. Ensure that an operator is always at the constraint working the product through it. Do this by staggering lunches and breaks, and cross training to ensure multiple people can work the constraint. Treat the person working the constraint like a heart surgeon. Everything is always there ready for them to do their job. They don’t have to go looking or wait for anything!!
  6. Establish procedures to ensure the constraint “NEVER RUNS DRY”. This includes material flow management, buffers, inventories, early deliveries, and expediting material so that they are always there at the constraint, ready for use.
  7. Every constraint needs to be a planned maintenance #1 priority so when maintenance is preformed it take the minimum amount of time away from running product on the operation. Notice I said a planned maintenance NOT no maintenance. I do not remember how many times I have heard that “we could not afford to stop for maintenance” but they ended up having to stop for repairs caused by no maintenance. Those repairs took, on average, 10 times longer to do. Maintenance is cheap and can be done off hours on constraint equipment.

Well there you have how to exploit a constraint in your processes. Next week I will address subordination of a constraint the third of five steps in constraint management. As always if, you have questions or comments please feel free to contact me by leaving a comment below, emailing me, calling me, or leaving a comment on my website.


Bersbach Consulting
Peter Bersbach
Six Sigma Master Black Belt
http://sixsigmatrainingconsulting.com
peter@bersbach.com
1.520.829.0090

Identifying your Process Constraints

Thursday, May 27th, 2010

constraint management

Some times the hardiest thing is to find your process constraint. Remember, a constraint is any resource with less throughput than the demand placed on it. They regulate the output of your whole process. First, you need to understand “demand”. Demand is not what the supervisor wants, although many times it feels like it if the supervisor does not understand constraint management. Demand is the rate at which you need to run the process to meet customer needs or demands. If you are not making it for a customer then it is not a demand you really need to meet.

Where do we look for possible candidates as possible constraints? We go walk the process and look for:

  • Areas where a lot of WIP (Work in Process) or material is waiting for processing. This is one of the Seven Types of Wastes.
  • Areas that work a lot of overtime. This is not just paid overtime but also unpaid. If your company is good, employees many times will work extra hours just to make things happen sooner, this counts as overtime also.

At those operations that you see the above happening review the following:

  • Spaghetti Charts (Physical Process Flow Chart) of these operations. Is there a lot of movement?
  • Line balance at these operations. Is the product balance uneven?
  • Constraint Capacity. Is capacity below the demand?
  • The demand on the operation. Are the demands real?

If the answer to any of these four questions is yes this step is a possible constraint.

To validate these steps as a constraint we need to use TAKT time to understand the constraint need. TAKT time is the time which should be taken to produce a product based on customer demand. With that said if every step or operation of a process is working at or above that rate then the whole process is meeting the customer demand. It only takes one step of the process to be below that TAKT time to make the whole process fail to meet the demand placed upon it. Once we have the TAKT time, we can compare it to the actual throughput and validate the step as a constraint or not. TAKT time is the total net operating time per shift or day, divided by the total customer(s) requirements needed per shift or day. Net operating time is the total time minus breaks and lunch (if things are not running during that time). For example lets say your customer demands are 1000 (parts, transactions, assemblies) per shift and a shift is 8 hours or 480 minutes. Now lets say that we have two 20 minute breaks during the shift and no lunch breaks (employees do take lunch but the operation is still running). That means our net operating time is 440 minutes (480- 20- 20= 440). So TAKT time is 440/1000 = .44 minutes or (.44min * 60 seconds) 26.4 seconds per item. That means that in this process every step has to complete their tasks in 26.4 seconds.

Once you have the TAKT time for each of the process step that you had identified above then you can list all those steps by TAKT time and actual time. Those that exceed the TAKT time are constraints; those that do not exceed the TAKT time are not constraints.

Well there you have how to identify a constraint in your processes. Next week I will address exploiting the constraint the second of five steps in constraint management. As always if, you have questions or comments please feel free to contact me by leaving a comment below, emailing me, calling me, or leaving a comment on my website.


Bersbach Consulting
Peter Bersbach
Six Sigma Master Black Belt
http://sixsigmatrainingconsulting.com
peter@bersbach.com
1.520.829.0090