Workshop «Shaft alignment and dynamic balancing»
We invite technical specialists to participate in the training course on the topic «Shaft alignment and dynamic balancing» which will take place on 04-05 April, 2019 in Germany (Lubeck). The workshop is arranged for specialists in quality, service engineers, mechanics and power engineers who are responsible for the reliability of machines and industrial equipment.

BALTECH GmbH
Kronsforder Allee 45,
23560 Lübeck
Germany
Tel: +49 (0) 451-370-87-700
E-Mail: info@baltech.biz
 
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Articles -- Efficiency enhancement


Production equipment efficiency enhancement and maintenance cost reduction

Maintenance costs reduction and the production equipment reliability enhancement are the main priorities of any industrial complex. Very often factory managers address to consulting firms for the theoretical calculation of the required annual costs for production, repair and diagnostics of production equipment.

BALTECH GmbH points out that most often the experienced specialists of your company have all the necessary knowledge to improve the production efficiency and. So use your own internal resources.

The present level of development of industrial technologies makes high demands on the reliability of the equipment, as well as the efficient and effective operation of production equipment with the minimum financial expenses and time consumption. In various industries the maintenance and repair system (further- MRO system) is not uniquely defined.

In connection with process optimization, restructuring of all industry sectors and enterprise departments two key factors move to the forefront - the used production equipment and the MRO system. Due to the financial difficulties the used production equipment is sometimes can’t be upgraded, so the MRO system is the most priority task in all the industries. This problem directly affects the enterprise efficiency.

To correct the problems and determine approaches to organization of maintenance department it is necessary to identify the key factors to ensure the machinery reliability and availability (e.g., dynamic equipment - pumps, fans, motors, gearboxes, compressors, etc.)

The machinery reliability is based on the mandatory application of new tools, methods of industrial equipment monitoring and set- up, and requires a comprehensive approach to solving engineering problems.

The machinery efficiency (i.e. correspondence to the given technical characteristics during a specific period of time) and the restoration of their main characteristics are achieved by means of the MRO system.

According to the Reliability Technologies Conception the goal of the MRO system is equipment condition monitoring during its entire life. The MRO system allows ensuring the high level of the machinery availability and efficiency with the minimum time consumption and repair costs.

The MRO system should be directed at improving the equipment utilization rate, which is described by the following equation:

(1.1.)

where ttot- running hours;tγ and tm - downtime (connected repair and maintenance).

It is logical to assume that in order to increase the KT one should increase the machinery failure interval and reduce downtime connected with repair and maintenance. At the same time the quality of the maintenance performed can reduce the number of repairs.

Five approaches to maintenance and repair

If you work in the industry long enough, you have probably observed all the different forms of maintenance. Today there are five main maintenance forms:

1) Reactive Maintenance;

2) Scheduled Maintenance;

3) Maintenance Based on the Actual Condition;

4) Proactive Maintenance;

5) Reliability Technology Conception (comprehensive approach to the analysis and maintenance)

 

Table1. Maintenance and repair forms

Table1, Reliability technologies, IORS-2020

Below are the advantages and disadvantages of the MRO forms:

Table 2. Advantages and disadvantages of the MRO forms

Table2, Reliability, Shaft alignment, Vibration, Thermography

As practice shows, no companies use only one of the above mentioned types of the MRO system. Moreover, the transfer from the Scheduled Maintenance to Maintenance Based on the Actual Conditions connected with rebuilding the entire structure of the MRO system, and in many cases it has the opposite effect - return to the Scheduled Maintenance . The reason for this is inconsistency in planning of activities of different departments, lack of trained personnel and weak technical equipping of repair services.

The transfer to the advanced maintenance form (Maintenance Based on the Actual Condition and Proactive Maintenance) is impossible without a competent technical diagnostics service. Also it’s wrong that the goal of the Maintenance Based on the Actual Condition is to eliminate equipment failures by identifying existing or developing defects only based on vibration characteristics. The Maintenance Based on the Actual Condition and the Proactive Maintenance should be based on the mandatory use of a number of methods of the equipment condition monitoring and technical diagnostics that together allows identifying the all the defects of production equipment.

The Technology Reliability Conception is a conceptual approach to the establishment of an effective system of maintenance and repair of industrial equipment based on a comprehensive study of direct causes of faults and identifying gaps in the organizational structure. The developed method of solving the problem and improving the machinery reliability ensures cost-effective results related to the proper transfer to the conceptual maintenance suitable to a particular company.

Technology Reliability Conception (comprehensive approach to the equipment reliability)

Now it is clear that depending on a branch of industry and company business activity all the maintenance forms should be used together in different proportions, and only in this case the maximum economic benefit can be reached. Below is an example of the first stage of the technical audit conducted at one of the metallurgical enterprises.

100% is 100 pieces of the dynamic equipment. The conducted audit revealed that even new equipment has a reduced initial reliability coefficient due to improper technical task, improper transportation and storage, and low-quality assembly of the ventilating units on a foundation that doesn’t correspond to the construction requirements.

The main stages of the Reliability Technologies Conception implementation

The Reliability Technologies Conception implementation consists of six main steps (step by step). Each of the following steps is based on the solution of problems (tasks) of the previous level with a purpose of its complete solution.

Step 1: Problem identification

Determination of the problem related to the equipment reliability enhancement is a fundamental step in solving this problem. At this stage it is a comprehensive approach that determines the economic impact of this program implementation.

Individual approach to solving the problem is defined by a set of tools used to detect and study the key points.

Among the tools is a comprehensive assessment of long-term statistics conducted by trained technical auditor of your company (specialists of technical diagnostics and non-destructive testing department), or estimation of the machinery defects, carried out by a contracting service organization.

Among the key points are:

  • analysis of the equipment overall condition;
  • analysis of the equipment repeated failures / malfunctions;
  • analysis of the devices and tools used for the equipment maintenance;
  • analysis of the staff skill level or level of a contracting service organization;
  • analysis of the maintenance type used at the enterprise;
  • analysis of the special moments of the used maintenance form;
  • analysis of the overall efficiency level of the enterprise, including the efficiency coefficient and performance, expenses for spare parts and maintenance;
  • analysis of the overall level of industrial culture and quality management system;
  • analysis of the system of purchase, transportation and storage of equipment and lubricants.

Stage 2. Detection of the problem components

At this stage it is necessary to define the problem components. It will help to identify the weaknesses of the enterprise structure.

Stage 3. Defining a strategy and a problem solution plan

The strategy of the problem of increasing the equipment reliability determines the degree and level of detecting the dangerous moments. It can be partial (removal of only the most problem issues) or comprehensive (complex) one.

It is important to determine what should be corrected: cause or consequence of the problem and / or what should be corrected in the first place.

The strategy and problem solution plan are determined based on the proposal of the specialists of technical diagnostics and non-destructive testing department or contracting service organization.

Stage 4.Selection of reliable means of technical solutions and development of staff skill upgrading program

The selection of means of technical solutions is determined by the appropriateness of their use on the basis of the calculation of economic effect resulted from their implementation. During the calculation one should be guided by selected criteria and requirements to the reliability level 1R, 2R or 3R (R-Reliability). Means of technical solutions are selected by the enterprise on the basis of the proposals of the experienced technicians of this enterprise and the concept developed by a group of technical auditors. Development of an internal reliability standard and certification "Reliability Technologies" should be carried out (our recommendation) on the basis of the process approach 3R (Responsible people and their powers, the Reliability policy and necessary Resources).

Stage 5. Comprehensive problem solution

Based on the 3rd and 4th stages of the program a complex solution of the equipment reliability enhancement problem is formed. If the company is certified for quality management system, the quality manager should make corrections in the internal quality management structure with account of the requirements of the technical department (e.g., department of chief mechanic or chief power engineer).

Implementation of the comprehensive solution or certification according to the standard “Reliability Technology” should be carried out by certified internal or external auditors.

Stage 6. Control of results of the program implementation

The process of assessing the equipment reliability, correction and implementation of improvements should be made in approved intervals independent from the target reliability level.

The customer satisfaction from the program implementation should play a key role, therefore a control, analysis and result improvement is extremely important.

If required, the whole conception should be implemented in accordance with the requirements of technical supervision in the field of expertise of industrial safety of hazardous production objects (if there is a technical supervision at your enterprise).

The specialists of the technical diagnostics and non-destructive testing department should be taken as a basis. Let’s consider these terms in more details.

Technical diagnostics is detection and study of defect signs in the machinery intended to predict the possible deviations in their operation modes. From the definition it is clear that the study (analysis) of defect signs should be always recorded in the statistics table.

Now let’s define the main tasks of the technical diagnostics and non-destructive testing and reliability assurance.

Relying on the main achievements of the technical diagnostics and non-destructive testing it is necessary to carry out optimization of monitored parameters according to several criteria (for example, all the diagnostics and repair data is stored in a MRO computerized control system. It is necessary to determine the necessary and sufficient conditions for the selection of hardware of functional and test diagnostics depending on the selected methods of predicting the technical condition of industrial equipment, as well as tools and forms of documents suitable for analysis (e.g., the BALTECH SA-4300 alignment system, the BALTECH VP-3470 dynamic balancing system, analyzers, non-contact thermometers BALTECH TL-0215C, the BALTECH TR-01800 infrared camera, the BALTECH HI-1630 induction heater, bearing incoming inspection stands, removers, stationary control systems operating under the rules of the BALTECH-Expert single automated database). It is necessary to define thresholds for configuration of the developing defect severity and set the value of the danger zone. It is necessary to understand the difference between monitoring and diagnostics, no matter what kind of system you use (portable, stand or stationary one).

Monitoring is detection of the machinery current condition;

  • comparison of diagnostics parameters with threshold values;
  • forecast of diagnostics parameter changes

Diagnostics is identification of causes and conditions that lead to failure, and making reasoned decisions on their elimination.

  • definition of the type and amount of each defect;
  • comparison of the defect amount with threshold values;
  • forecast (detection of residual life);

Depending on the condition of the equipment: non-operating condition , partial working condition (operation only below the nominal load) and working condition, stages and measurement types are selected.

Stages of diagnostics measurements:

  • After installation or repair;
  • After run-in operation or during operation;
  • After disturbance of technological mode;
  • Before repair stop;,

Types of diagnostics measurements:

Diagnostics measurements and monitoring of the equipment can be divided into two types:

1. Control measurements:

  • current,
  • complete,

2. Special measurements.

Today one of the main international standards for determination of criteria of the machinery condition evaluation is ISO 10816. This standard is the basic document for the development of guidelines on the machinery vibration measurement and analysis. The evaluation criteria for specific types of machines should be established in the appropriate individual standards. The ISO 10816 specifies only approximate criteria that can be used in the absence of appropriate normative documents. It allows determining the upper limits expressed in RMS vibration velocity Vrms, mm / s, for machinery of different classes:

  • Class 1 - Individual parts of engines and machines integrally connected with the complete machine in its normal operating condition.(Production electrical motors of up to 15 kW are typical examples of machines in this category.
  • Class 2 - Medium-sized machines, (typically electrical motors with 15 to 875 kW output) without special foundations, rigidly mounted engines or machines (up to 300 kW) on special foundations.
  • Class 3 - Large prime movers and other large machines with rotating masses on rigid and heavy foundations, which are relatively stiff in the direction of vibration measurement.
  • Class 4 - Large prime movers and other large machines with rotating masses on foundations, which are relatively soft in the direction of vibration measurement (for example turbo generator sets and gas turbines of up to 10 MW).

Fortunately, in all industries there are three key factors determining the overall success of the enterprise:

  - Common understanding of the need of reformations (goal setting and selection of the solution method);

  - Aspiring to implementation of new advanced technologies and modern hardware;

  -Desire to maintain the process of introducing new technologies and new approaches to the equipment maintenance.

  We wish a successful development to all enterprises by optimizing the repair costs using long-term statistics and their own experienced specialists. BALTECH has more than 2,000 customers worldwide. We extend our many thanks to our customers and invite everybody to the Reliability Technologies courses.

Conclusions:

The maintenance cost reduction and reliability enhancement of the production equipment can be carried out using a lot of advanced technologies. The developed countries have been using the TRIZ technology (Theory of solving of inventive problems), Lean Production, Reliability Technologies, as well as various forms of periodic technical audit and consulting.

We know from our experience that first it’s most important to clearly define the goals and objectives of the production optimization, for example, financial costs reduction by 5%, creating an optimal service strategy or increasing the reliability of the production equipment.

It is always necessary to introduce improvements to the enterprises by using your own experience and statistics data of all the departments, which will allow getting the best results and being competitive in the market.