Reduce downtime? Why do we need to do this? Well manufacturing industries these days focus on improving their productivity. One best approach to improve productivity is to reduce the downtime.
Productivity in simple terms refers to the ratio of the output to input. Productivity = Output / Input.
To have an increase in productivity there are four possible approaches that are taken up by the manufacturing industries. They are listed below
- Decrease in input and increase in output
- Small increase in input and Proportionately higher increase in Output
- Decrease in the input and no change in the output
- Small decrease in input and Proportionately higher decrease in Output
As a simple saying goes this way, ” Any thing that cannot be measured cannot be improved” first we need to understand the measure for productivity.
Industries use the term OEE to understand how effective a process is utilized. I have posted a blog on What is OEE? How to calculate OEE. I recommend you to read it to have a crisp and clear idea about OEE.
The Overall Equipment Effectiveness (OEE) measures using three parameters namely Availability, Performance and Quality.
This particular blog focuses on ways to improve productivity by reducing downtime. There are many ways to do it but to keep it simple I am going to share 3 important ways to reduce downtime. Let us see one by one
1. Preventive maintenance:
Effective and meticulous Preventive maintenance produces good results in terms of downtime reduction. Any breakdown doesn’t just like that happen. First it shows abnormality and when the abnormality is ignored the abnormality turns into a breakdown. There are some simple preventive maintenance things you can practice in your manufacturing plant to reduce down time
CLIRT- CLIRT stands for Cleaning, Lubrication, Inspection and Retightening. This is an important part of the Total Productive Maintenance (TPM) which targets Zero defects, zero breakdown and Zero accidents.
While doing the CLIRT every day during the start of the shift various things come into light. If the oil level is low it is identified and immediately filled so that the machine does not stop due to oil level low alarm. Similarly when the cleaning is done every area is accessed so that if there are any abnormalities it is immediately brought into attention and solved then and there. These activities reduce the chances of downtime on a shop floor.
Time based maintenance – In the process of continuous usage certain things tend to fail. For example a filer in the coolant pump is subject to getting blocked on continuous usage. It is good to replace the same on a time basis. If the filter clog tends to happen once in 7 to 8 days, we may plan to replace the same once in 5 days to ensure there is downtime due to the filter clog.
The replacement can be done at a non operating time such as after shift hours, week end off etc. Also an additional cleaned filter can be kept as a standby so that even in odd cases if we require any change in filter it can be done in a very quick time so that the down time is very less.
A similar planning and execution for the preventive maintenance activities will largely help in reducing the down time.
2. Tools and Fixtures Presetting
The second opportunity in the down time reduction in manufacturing industries is from reducing the Tool change and Setup change over time. Tool changes are needed to be done mostly unexpectedly. Even though there is a system to reduce the unexpected tool change by monitoring the Tool life and changing it accordingly, the unexpected tool breakage and quality problems due to tool problems do occur.
The time taken to change the tool and gauge corrections required after the tool change incurs down time and also has chances to produce defective components.
The best way to reduce the downtime due to tool change is to do a presetting of the tools. Many cases we see people doing it but not properly. The presetting has to be done such that the tool that is about to be changed does not require any major adjustments. In case of CNC machines the tools can be set to the height that is already in use in the machines. If there are any runout settings to be done to the spindle these things can also be planned and done during non manufacturing hours.
Tools that are sensitive to break and tools that are sensitive to produce quality problems can be identified as potential requirements and such tools can be set in increased numbers.
When there is a requirement for the tool change only time that is supposed to be spared is the time taken to remove and fix the new tool to the machine.
Another thing that consumes time resulting in downtime is the change over time. Like what we do the tool change we must prepare the required fixtures, clamps, tools etc. before the start of the change over. The change in design of the fixing and removal of fixtures will be highly required to facilitate quick changeovers.
Any presetting for Tools or Fixtures will be effective if it is done with a presetting checklist and presetting tag. The presetting checklist will ensure that the preparation made is perfect without any missed outs items or activities and the presetting tag will give a clear communication to the user who uses the preset tools and fixtures.
3. Training and Communication
Training is another important aspect to look into when we aspire to improve productivity. Many manufacturing industries want to keep their workers in the dark about the process. Such workmen tend to look for the supervisors and other senior persons to solve the problems that they face in the manufacturing process. When there is more dependability on other persons to solve issues that you are facing it is very natural that issues tend to solve after a large amount of time consumption.
Training is a magic word to avoid this downtime. The person working in a machine/process must be aware of the technical aspects of the process so that when there is a need for tool change, fixture change and measurement and adjustment etc the required things can be handled by the person working with the machine. This will not only reduce the downtime but also improve the morale of the person to perform even better.
Good communication will help to avoid problems in the manufacturing shop floor. Many cases due to miscommunications there is increased downtime. Usually the communication gap is noticed between the personals working in different shifts where they do not have the opportunity to meet and communicate. Best way to bridge the communication gap is by writing down the activities in a log book at the end of the shift. These written information not only bridges the communication gap but also stays as a record for future reference.
When all these three vital areas are put into practice the results will be definitely worth the efforts. The productivity improvement does not stop only with these downtime reductions; it can also be done by improving the quality and performance in the process. We may have a blog post for the same in future.
We believe that we have helped you to think on a few vital areas that are needed to be focused on for improving the productivity in the manufacturing process. We do believe you will benefit from the actions that you do from the learnings. We would be glad if you could revert with your feedback in the comment section below.