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How does free work order software (not) address maintenance challenges?
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How does free work order software (not) address maintenance challenges?

  • Katarina Knafelj Jakovac

    March 14, 2024

Computer programs are an indispensable tool in maintenance management. They have applications in various industrial sectors, from complex oil and gas industries, through transportation, to mineral water production, to name just a few.

Numerous technological companies have developed software for managing work orders and equipment maintenance of various levels of complexity and price range for end-users.

There are computer software programs that are so complex that you need to employ an entire department of experts for their use and development. The cost of a license and support for such software ranges from 1500 euros to 2700 euros per month according to an analysis by the ScienceSoft portal.

In contrast, there are free software programs that are easy to use and cost nothing for the user. An old saying goes: You get what you pay for, but is that really the case when it comes to computer software for managing work orders?

Using the practical example of maintenance of a belt drive and defining KPIs for measuring mean time between failures, we will see the advantages and disadvantages of using free work order software and its role in improving maintenance.

Example 1) Maintenance of a Belt Drive

Belts are the main element of a belt drive used in certain types of rotating equipment such as air conditioner fans or air blowers.

According to research by the Reliabilityweb portal, more than 84% of V-belts and toothed belts shown in Figure 1. never reach their intended service life due to improper installation, incorrect type, or improper storage.

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Image 1: V-Belt (Source) and Timing Belt (Source)

The consequences of such situations are unexpected interruptions in the operation of rotating equipment due to belt breakage or slippage, loss of capacity, and increased costs due to downtime in the production process or high electricity consumption.

We will see how digital work orders for handling, assembly, and corrective maintenance of belt drives contribute to extending the service life and trouble-free operation, as well as timely detection of faults and prevention of breakdowns.

To begin with, before any work in the facility, adhere to all prescribed safety measures and use personal protective equipment.

You create a digital work order in maintenance management software by defining the machine on which the work will be performed, a detailed description of the necessary work, tools, and spare parts, and the final acceptable deadline for completing the work.

The description of the work is as follows:

When dismantling, loosen the foundation screws of the drive motor and move it until the existing belts hang loosely and then remove them without applying force.

Forcibly pulling the belts can cause injuries to employees and damage the pulleys. For the same reason, do not remove the belts from the pulleys with a screwdriver.

After removing the belts, thoroughly inspect them along their entire length on the outer and inner sides. Uneven wear on a particular part of the inner side indicates a problem with the pulley design or lack of maintenance.

Visually inspect and replace the pulley if it shows signs of severe wear, rust, cracking, deep cracks, or a bent groove side.

Grooves that shine or appear polished also indicate material wear. Do not clean the pulley by sandblasting or grinding with a hand grinder as this will further remove material from the already worn surface of the pulley, leading to faster wear and belt breakage or the appearance of deep cracks on the pulley.

Measure the groove depth on the pulley to check the wear and if pulley replacement is needed. The total material wear in the depth of each groove should not exceed 0.8 mm.

Belts and pulleys must be properly aligned, preferably using a laser alignment device.

Belt manufacturers recommend allowable deviation during alignment up to max. 0.5°.

Before alignment, check in the machine user manual what deviations are allowed. When aligning the pulleys, place the laser device on the smaller pulley and align the larger pulley to it as shown in Figure 2.

The laser device must indicate alignment in all 3 degrees of freedom - axial, angular horizontal, and angular tilt.

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Image 2: Laser Belt Alignment (Source)

When multiple belts on a pulley need to be replaced, replace all belts at once with new belts from the same manufacturer.

When taking new belts from the warehouse, check the belt length, i.e., make sure you have chosen the same set for one machine. There have been cases where the same manufacturer has supplied belts of different dimensions for the same machine.

Never change only one belt and leave the remaining belts in place. This situation leads to uneven load distribution and premature wear of the belts or pulleys.

When mounting a new belt, make sure the belts and pulley groove match each other. Do not forcefully try to insert the belt into the pulley groove or use a screwdriver in the process as this will damage the belt, pulley, or both.

When the belt is mounted, start moving the electric motor until the belt is tensioned. First, check the motor feet for the presence of a soft foot. If a soft foot is present, remove it first and then proceed with work on the belts. The reading of the existing motor deflection must not exceed 0.05 mm.

Use a tension meter and check if the belt tension is in accordance with the specifications. There are other, more modern and expensive devices for checking belt tension, but some of them are not allowed to operate in explosion hazardous zones.

If necessary, check with the belt manufacturer what the allowed belt tension values are depending on the machine's operating load. The appropriate belt tension is the minimum required value to prevent belt slippage from the pulley at maximum operating load.

If you don't have access to data, you can use a tension meter by attaching it to the middle of the belt length and then pulling downwards, as shown in Figure 3.

Monitor how much deflection occurs and record it as shown in Figure 4. Belts must be tensioned to the extent that the force required to pull the belt is equal to the maximum allowable force prescribed by the manufacturer for the mounted belt.

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Image 3: Force Acting on the Belt to Check Tension and Deflection

Rotate the pulley by hand several times in the direction of the electric motor rotation and adjust the belt tension if necessary. Once again, check the belt fit in the pulley grooves and adjust if necessary.

Now the foundation screws of the electric motor need to be tightened to the specified torque, check the machine documentation for the prescribed torque value.

Finally, install the protective cover over the belt drive. Only then can the electric motor be connected to the power source and the machine started.

After that, listen and check for any unusual noise, increased vibrations, or overheating. Lubrication may be required, belts may need to be retightened or loosened, and alignment checked to ensure proper operation.

Record the date of belt replacement, type, and number of belts in the digital machine card, briefly describe the condition of the old belts, and state the reason for replacement (e.g., routine replacement, preventive maintenance, etc.).

After each alignment, a protocol on the work performed is filled out, for critical machines the protocol is mandatory while for non-critical machines it is filled out after general servicing.

Figure 4 shows an example of an alignment protocol where alignment values, force, and measured deflection are entered.

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Image 4: Alignment Protocol and Measured Deflection

Manufacturers have an application on their websites for checking. The link provides a simple calculator for calculating belt tension, but you will need to convert the units from imperial to SI because it is an American manufacturer.

Belts should not produce an irritating squealing sound when the machine starts operating if they are properly tightened.

The squealing sound is a sign that the belts are not suitable, not properly aligned in the pulley grooves, or not properly tensioned, and sometimes it is a combination of all of these.

With some belts, a break-in or running-in period may be necessary for the belt to fully seat in the pulley groove and achieve reliable operation.

In such cases, it is recommended to stop the machine and check and tighten the belt after the machine has been operating at full load for 30 minutes, 24 hours, and 48 hours. Be sure to check the machine documentation or consult the belt manufacturer if you encounter such a situation.

Required tools: laser alignment device, tension gauge, torque wrench, appropriate size wrench, antistatic material wiping cloth. All tools must be made of non-sparking metal.

Required spare parts: toothed or V-belts of the required length and width, depending on what the manufacturer has specified in the user manual.

Spare parts need to be planned in the computer software and ordered in advance so that they are available in the warehouse by the start date of the maintenance work.

Calculation for checking belt tension

Belt tension is checked by applying force and measuring or calculating the belt deflection shown in image 3.

The force required to tension the belt is calculated using the formula:

F=(PX50)/vF = (P X 50) / v

where
F – force, N
P – power of the driving machine, kW
v – belt sliding speed on the pulley, m/s

The speed is calculated as follows

v=(SXNXn)/60000v = (S X N X n) / 60000

S – distance between the centers of two pulleys shown in image 3, mm
N – number of grooves in the pulley
n – speed of rotation of the driving machine, rpm
The minimum tensioning force is calculated by the formula:

F=(PX25)/vF = (P X 25) / v

The allowable belt deflection d is calculated by the formula:

d=S/50d = S / 50

Let's take an example of an electric motor with a power of 60 kW, a rotation speed of 2500 rpm, which drives a fan.

Both machine pulleys have 3 grooves, meaning the driving and driven machines are connected by a belt drive consisting of 3 belts.

The distance between the centers of two pulleys will be 1750 mm.

The belt sliding speed will be:

v=(SXNXn)/60000v = (S X N X n) / 60000

v=(1750X3X2500)/60000=2187.5mm/s=2.2m/sv = ( 1750 X 3 X 2500) / 60000 = 2187.5 mm/s = 2.2 m/s

The minimum tensioning force is:

F=(PX25)/vF = (P X 25) / v

F=(60X25)/2.2=682NF = (60 X 25) / 2.2 = 682 N

The tensioning force is:

F=(PX50)/v=(60X50)/2.2=1363.6NF = (P X 50) / v = (60 X 50) / 2.2 = 1363.6 N

The allowable belt deflection for the given parameters will be:

d=S/50=1750/50=35mmd = S / 50 = 1750 / 50 = 35 mm

All data should be recorded and stored in maintenance management software.

Example 2) Monitoring indicators of reliable machine operation

Machine failures happen sooner or later, it's important to be prepared for them when they occur unexpectedly.

A failure can be partial or it can be a complete breakdown of the machine, fundamentally a failure is any event that prevents the machine from fulfilling its function, e.g., a pump does not pump glycol, a separator does not separate dirt particles from fuel, etc.

Even when a pump partially pumps the working medium, we say it's a failure because it's unable to pump the required amounts for an uninterrupted production process.

Eliminating failures significantly reduces their impact on the production process and maintenance costs. To efficiently address failures, there are certain calculations used to monitor the condition of machines.

Understanding the method of calculation eliminates the need to guess about the condition of the equipment and provides management with the information needed to make business decisions.

For quality results, it is necessary to collect reliable data on machine operation in a computerized maintenance management system (CMMS): number of failures, number of machine operating hours (total number of weekly working hours minus the number of hours the machine is idle), and the number of hours spent on maintenance activities.

Inaccurate data renders the calculation useless for making decisions about improving business processes and production.

Occasionally incorrect data distorts the picture, and constantly neglecting to enter data prevents assessments of the existing state of the machines because we end up in a situation where everything is working but we don't know how.

Indicators of successful machine operation are important for every production-oriented company. Monitoring the reliability of equipment is a daily requirement of every maintenance department.

Recording and monitoring failures is useful, so let's see what lies behind the acronyms MTTR, MTBF, and MTTF because their values indicate what is happening with machines and equipment.

  • Mean Time Between Failures (MTBF)

The most well-known indicator is the mean time between failures MTBF, which measures the time elapsed from one mechanical or electrical failure to the next failure while the machine is in normal operation.

The MTBF indicator measures the predicted time of how long the machine will work before the next unplanned failure occurs. In fact,

MTBF is a prediction of when the next failure will occur.

MTBF is calculated by dividing the total machine operating time by the total number of failures over time.

MTBF=Totaloperatingtime/numberoffailuresMTBF = Total operating time / number of failures

MTBF is measured only for technological systems that can be repaired and for failures caused by damage that cause plant shutdowns depending on the duration of repair of the failed machine.

The time that the plant spends in shutdown for planned maintenance activities is not taken into account. The higher the MTBF value, the longer the machine operates without failure.

Let's take an example of a wastewater pump that operates for 12 hours during the week and fails 3 times.

MTBF will be

MTBF=127/3=28hMTBF = 12*7 / 3 = 28 h

where the repair time is not included.

MTBF is most commonly influenced by human factors, where a low value indicates inadequate equipment handling or poorly performed previous repairs. MTBF is an important performance indicator for machines, especially critical equipment.

Equipment manufacturers use MTBF as a quantitative reliability indicator during the design and production phase of machines.

Planned maintenance work is not taken into account, and the mean time between failures can be used when calculating inspection periods or for preventive equipment replacements.

If it is known that the machine will operate for a certain number of hours before the next failure occurs, introducing preventive procedures reduces the likelihood of failure, extends the machine's operating interval, and increases reliability.

  • Mean Time To Failure (MTTF)

Mean Time To Failure (MTTF) is the basic indicator of reliability for technological systems that are not repairable.

It represents the total time that the machine spends in operation before a failure occurs.

Mean time between failures is commonly known as the machine's life span or equipment item. It is calculated for a large number of identical machines or equipment over a longer period of time by observing when the failure occurred.

In production, the mean time to failure is determined to assess the reliability of a group of machines and does not take into account repair times. Therefore, MTTF is the ratio of the total number of machine hours to the total number of machines being monitored.

MTTF=Totaloperatinghours/TotalnumberofmachinesMTTF = Total operating hours / Total number of machines

For the previously mentioned wastewater pump assumption that there are 6 such pumps at the plant that we observe in a week, and they all broke down.

The first one broke down after 10 hours of operation, the second after 20 hours, and the third after 36 hours. The mean time to failure will be

MTTF=(10+20+36)/6=11hMTTF = (10+20+36) / 6 = 11h

The average time to failure of each pump is 11 hours, indicating that this type of pump fails after a small number of operating hours, or it has lower reliability. Increasing the mean time between 2 failures is achieved by replacing them with better quality pumps or those made of stronger materials.

MTTF is an indicator of the life cycle of a specific machine or group of machines of the same type or model. It is applied to rotating equipment, automobiles, and a wide range of products, even light bulbs.

It is used to assess how long a part within a machine or observed piece of equipment will last, especially in process plants that are extremely sensitive to unplanned shutdowns caused by failures.

MTTF is the first reliability indicator aimed at extending the machine's life. The lower the MTTF, the greater the number of production stops and breaches of deadlines.

  • Mean Time To Repair (MTTR)

Mean Time To Repair is the time it takes for the machine or machine system to be repaired and fully functional again.

Time is measured from the start of repair to the moment the machine is restarted and operates at full capacity again, including repair time, testing time, and return to normal operating conditions.

MTTR time is calculated by dividing the total maintenance time by the total number of repairs during a defined period.

The average repair time compared to the average time to return to functionality is the time from when the fault is first detected until full functionality is restored, including all previously mentioned and includes time for fault notification and diagnostic time.

MTTR=Totalmaintenancetime/TotalnumberofrepairsMTTR = Total maintenance time / Total number of repairs

For example, the mentioned centrifugal pump in the water treatment plant breaks down 3 times in a week. The duration of each repair is 2 hours. Then

MTTR=2hours60min/3repairs=40minutesMTTR = 2 hours * 60 min / 3 repairs = 40 minutes

This is an extreme example in terms of frequency of failures, but you got the idea.

Not every failure is equally complex, while some failures are resolved by mechanics for days, another type of failure can be resolved in a few minutes.

Therefore, the mean time to repair is the averaged repair duration. There is a difference when an experienced professional is working on fault resolution, taking less time, and an employee with less experience takes longer for the same job.

Every efficient maintenance department will continuously aim to reduce the mean time to repair as much as possible.

One way is through proactive maintenance strategies such as preventive and predictive maintenance by monitoring the condition of machines and equipment and repairing the machine before the failure even occurs.

Another way is by constantly monitoring the quantity of spare parts and ensuring they are always available in stock to drastically reduce or eliminate waiting time for spare parts.

MTTR helps in understanding how efficient the maintenance system of a particular process plant is in resolving failures by using a computerized maintenance management system (CMMS), proprietary tools, personnel, and spare parts.

Excessive downtime required for machine repair is every maintenance manager's worst nightmare because it increases the risk of unplanned production shutdowns and financial losses in production.

MTTR indicates when it is better to repair or replace a machine, the quantity and cost of available spare parts, and when to upgrade the machine.

One of the main goals of efficient maintenance is to ensure maximum availability of machines with efficient and safe operation.

MTTR, MTBF, and MTTF help you accurately determine when a machine failure will occur. This will help you develop better maintenance strategies and improve maintenance processes.

Any quality work order software has options for calculating and displaying mean time between failures, mean time to failure, and mean time to repair of company equipment.

This is valid provided that you accurately and promptly enter data on failures, create appropriate work orders, and enter feedback after each completed repair.

Why use free work order software?

  • If you are just starting out with your business and need to strictly manage the company's budget, using free work order software will help you avoid spending money on licenses, upgrades, customer support, and implementation.
  • It is easy to use: open-source software typically has very user-friendly interfaces and interactions.
  • If you have a lower level processing facility with only a few machines, one conveyor belt, and a very small amount of control and regulatory technology, such as in the case of producing craft beer in very small batches.

Examples from other areas where free work order software can be applied include a small boutique hotel with 10 rooms, a family-owned agricultural enterprise, or maintenance of a football stadium.

  • If you are unsure which type of computer software to choose for maintenance management and want to try out features and functionalities, free software specific to your industry will allow you to do so at no additional cost until you find what suits your needs.
  • If you don't have a spare parts warehouse or have a very small number of spare parts, you can easily archive the list in free software.
  • If you don't have your own repair workshops and everything is handled through an external contractor, you don't need work orders but rather a direct purchase order sent by email.
  • The required maintenance work is very simple and only requires the presence of one profession, for example, just an electrician or just a plumber. In this case, a digital work order is also not necessary, just a purchase order sent by email or a direct phone call to the contractor.
  • Your company has a maximum of 10 to 15 employees and does not have large administrative needs since the workload is divided.
  • You don't have a need for preventive maintenance work, or your needs are covered by a weekly/monthly contract with an external contractor/specialized company for a specific type of work.

Why not use free work order software?

  • If you have an established company with multiple departments that need to be networked and connected so that all have real-time access to data on equipment and maintenance.
  • If you have a large production volume.
  • Complex business processes for work orders because the software must maintain your actual business processes from creating work orders for maintenance needs to invoicing and closing orders after maintenance is completed.
  • Industrial plants with a higher level of complexity, such as a distillery for a globally known whiskey brand, edible oil production, or a fleet of trucks for transportation, are not ideal candidates for free work order software.
  • If you don't have access to IT customer support 24/7 to meet your production needs.
  • If you don't have access to training for employees using the software.
  • If you need an efficient inventory management application connected to work orders and other applications within the company.
  • If you employ more than 15 employees of different professions.
  • If you have your own repair workshops and need to simultaneously manage tool records and completed work.
  • If you have significant administrative and financial tracking needs for work orders and high-value spare parts.
  • When you need to review the realization of set maintenance goals and key performance indicators you previously defined and entered into the CMMS program every month.

In conclusion, free work order software has great potential for use in small hospitality and sports facilities, shopping centers, or family-owned businesses.

Complex industrial plants with a large number of diverse equipment, companies with numerous different departments and complex business processes are not ideal candidates for free work order software as such software unfortunately does not have the capacity to handle everything required.

Katarina Knafelj Jakovac
Katarina Knafelj Jakovac social media icon
March 14, 2024

Katarina Knafelj Jakovac holds Master degree in Mechanical engineering with long term work experience in Oil industry. She is Certified Reliability Leader specialized for mechanical equipment and operational excellence. Author of blog Strojarska Radionica (Mechanical Workshop) where she shares professional knowledge and personal experience in maintaining various rotating machines, machine systems and process equipment. Adores mechanics, thermal engineering and internal combustion engines. She is dedicated to the continuous improvement of machine maintenance and quality management of physical assets.