In this article we will be looking at equipment management covering machinery. To some this is an important area of valve manufacturing. Without adequate maintenance processes and systems it runs the risk of affecting the quality and manufacturing consistency of key components. I have seen many manufacturers with good management but also many that were not. The latter can be found throughout America, Europe, Asia and the Far East.
Unscheduled machinery downtimes should be minimized through properly controlled and organized maintenance. So, does the valve manufacturer:
- have a maintenance department,
- follow the recommendations of maintenance manuals, and
- have a structure to deliver a program that is reactive, preventative and predictive?
When this question is asked the response varies considerably from a very well organized department and effective preventative program to an almost zero preventative program where the
manufacture reacts to machinery problems as they occur. Downtimes are neither logged nor analyzed and the approach is a “quick fix” rather than “a long term sustainable solution”.
So what’s required?
The skill for the manufacturer is to apply appropriate maintenance levels to their machinery to minimise unscheduled downtime, control scheduled downtime and, as such, achieve maximum production efficiency. The manufacturer should demonstrate that they are gathering and analyzing data for schedule and unscheduled downtime.
They should follow ISO 9001 processes to establish root causes of failures and provide appropriate documentation and implement corrective actions. Failures should be analyzed and preventative and / or predictive maintenance established. Important meetings should be recorded. Where regular maintenance does occur an understanding of what spare parts should be established. Is there a procurement strategy for critical parts especially for those that have a long lead time?
The walk around by the auditor
Walking around the manufacturer facilities quickly informs the auditor of the level of maintenance that is being applied. Often daily check tick lists are located at each machine. Some are methodically completed whilst others are incomplete. I suspect sometimes the check lists are only there for “visitors”.
More critically are there lock-out and isolation procedures in place and applied when maintenance is being performed? Are the workers properly trained to apply lock-out? I am totally amazed to often witness that such precautions are not taken.
Where machinery is seen to be going through maintenance the auditor should question the manufacturer on their practices. Was this planned maintenance or not? Has effective lock-out been done? Another good indicator is how the manufacturer manages their tooling? What does the machine area look like at the beginning of the shift and at the end of the shift? Again is it well organized and clean or is it chaotic with tools not being put away and swarf left un-cleared?
Many manufacturers try to improve through various initiatives such as 5S, Lean Manufacturer, Six Sigma or Productive Maintenance. Whatever the system or combinations thereof the auditor should see a well organized manufacturing plant where machinery is seen to be clean, tidy and well maintained. Management should provide documentation such as schedules, bar charts, statistic analysis and minutes of meetings to demonstrate effective maintenance. Definition of machinery that requires preventative maintenance also gives rise to confusion. Should all machinery, whatever their function or duty, be included? For example some manufacturers for rough machining of valve components exclude these machines from the maintenance program. Is this correct?
Sub-suppliers - Machine shops
In previous articles I reviewed the control of sub-suppliers indicating the controls that should be in position. A lot of manufacturers subcontract many machining activities from rough machining to finished top works etc. When I have asked for sub-supplier documentation to demonstrate good preventative maintenance is being applied, nine times out of ten the answer is “we have used this machine shop for many years with no problems”. I often request to visit some of these machine shops. The valve manufacturer looks at me, bewildered but I still insist to visit. Within one such shop I observed many valve brands machined on machines that were not maintained. And I mean not maintained! Smoke rising from a gear box raised no concern. On / off switches were unsecure often with tape binding switches to the machine. I struggled to walk down the footpath between the rows of machines as mounds of swarf laid everywhere. I also had to duck as “metal debris” was flying from the turning of material on the adjacent machines.
In addition a sample check of instruments concluded they were not calibrated. In another sub-contracted machine shop balls were similarly being manufactured on machines that were not maintained and instruments were not calibrated.
Once again on both of these occasions I was proudly
presented with ISO 9001 Certification!
Where the above is observed the probability that the valve manufacture is lacking in other areas will be high.
Machined components and parts
During my audits I request to see documented evidence of dimensional checks of critical areas such as stuffing box tolerances and roughness to ensure compliance with the engineering specifications. For new sub-suppliers 100% dimensional checks should be done but in practice are often limited to sampling for example 5%. Too often such sample checks are not done. The manufacture inspectors do not have surface comparators. Visual inspection claimed to be 100% could identify non-conformances but the components are accepted. Today many end users are requiring consistent fugitive emission performance from production valves and are selecting test
valves from the supply chain and in some instances from each manufacturing plant within each company. The latest API valve test standards have likewise addressed this area. And guess what? Many valves are failing the fugitive emission tests. When the full supply chain is known and machining activities understood, current manufacturing practices are found to be seriously questionable. There is a significant “gap” between “the international code requirement” and “that delivered from the manufacturer.” This has to be challenged or the too often practice of providing “special machined valves for testing will continue”.
To some valve manufacturers the above may not be of interest or of importance in the quest to achieve quality valves and end user approvals. All I can advise is that end users will assess equipment
management, which includes machinery, and judge whether machined components and parts are of an acceptable quality or not.
Where the end user considers the valve company’s operation is just not good enough they will not give approval.
Many thanks for your time. Please advise if you have any comments or different views. They are most welcome.
Barrie Kirkman, BSc CEng MIMechE, writes a regular column for Valve World, bringing his own personal views from inside the valve business.
Barrie can be reached on: firstname.lastname@example.org.