A.1.1 Current Welding Operation

The customer has a diverse range of MIG welding equipment, including systems from both Esab and Kemppi (generally 300–350 amp). The fixtures have been manufactured in-house and provide simple location of the parts with manually operated clamps included as necessary.

Further details of the assemblies to be addressed are provided in Section A.2. The input parts are prepared in a separate facility, which includes the cutting and bending operations, close to the welding area. The parts are prepared in batches that can vary from 20 to 100 units. These are loaded into various bins and carriers, dependent on the type of part, and transported to the welding area.

Each welding station is separated by welding screens and generally comprises a table on which is mounted the relevant welding fixtures for the part to be processed. Welding fixtures are stored adjacent to the welding area. Each welding station is equipped with one set of MIG welding equipment and is normally occupied by one welder. In total there are 20 welding stations.

The welding facility operates two shifts, 5 days per week, with 8 hours per shift. There are 20 welders employed on days and 10 welders employed on the night shift. The parts for the assemblies to be produced are delivered to the welding station. Each welder will take parts as appropriate, locate them in the fixture, and perform the necessary welding operations. The assemblies are typically produced in stages, although for some of the smaller assemblies all the parts are located in the fixture prior to welding. Once an assembly is completed it is placed in a rack or bin located outside the welding station for removal and replacement when full.

A.1.2 Automation Concept

The customer intends to introduce a number of robot welding systems over time to automate the majority of the welding operations. This will be accomplished in a number of stages that must each be effective and financially viable. The customer is therefore looking for guidance as to how this would be best achieved and the types of automation solution that should be introduced.

This specification provides details of all the parts currently being produced (see Section A.2). It is understood that not all these will be processed by the first robot system. The vendor is therefore requested to consider which parts should be addressed by the first system to be introduced to ensure this first system achieves the objectives for the project, is fully utilised, and provides a sound introduction for robot welding.

The customer envisages an automation system concept that allows the operator to load individual parts into a fixture(s) at one work station, whilst the robot performs welding operations at a separate station. On completion of both operations, the robot and operator will then switch stations to allow the robot to continue welding whilst the operator unloads the welded part and loads new parts to be welded. It will be necessary to balance the welding time and the load/unload time to ensure the utilisation of the robot is maximised as well as ensuring the operator is utilised effectively.

The proposed solution must include the ability to change fixtures quickly and with repeatability to ensure changeover between different assemblies is accomplished with the minimum of down time. The concept must also provide easy access for the delivery of parts and the removal of completed assemblies.

The preference is to apply a standard concept across the full range of current products. The result would be a number of common cells that then have the flexibility to produce any of the assemblies. However, the customer is willing to consider alternative concepts for some parts, if there are significant benefits from this approach. The utilisation of the equipment will need to be more carefully considered if more than one concept is utilised. It is important to note that the automation concept must be flexible to cater for future product design changes and also new products.

The layout of the current welding facility is provided below. The location of the first robot cell is not yet defined, and the vendors are requested to consider how best to accommodate their proposed concept within the existing facility. This should take into account the need to continue with current production during the installation and commissioning phase for the robot cell. The customer recommends that the vendor make arrangements to visit the site to view the area and access for the equipment during installation.

A.2.1 Products

The assemblies currently produced are listed below, and drawings detailing the parts and welding requirements are enclosed.

A.2.2 Tolerances and Quality

The tolerances of the parts and also all assembly tolerances are included on the drawings. If the vendor identifies any concerns in relation to the ability to robot weld these parts and/or achieve the assembly tolerances, these must be identified in the proposal.

The weld requirements are identified on the drawings. In addition to meeting these, all welds must provide a good cosmetic appearance with minimal spatter. The customer will provide, to the selected vendor, a set of manually welded parts that will be used to determine the minimum acceptable standard from the robot cell.

The system will be required to achieve the above quality standard with a yield of 99.5%. The yield is defined as the number of acceptable parts produced per shift divided by the total number of parts welded over the same period.

A.2.3 Fixtures

For the first system, and the assemblies selected to be produced by that system, the customer expects the vendors to propose appropriate fixtures and to include these within the scope of supply. The vendors should include the most appropriate clamping techniques and fixture coding to provide for automatic selection of the appropriate robot programme based on the fixture(s) located within the cell.

Changeover of one fixture to another must be fast and repeatable. Vendors should include within their proposal the optimum method of achieving this to suit their chosen concept.

The vendor is to propose those assemblies that provide for the most effective operation of a single robot cell, as well as the most cost effective solution. The customer intends the cell to operate in line with the current operational times of the welding facility, that is, over two shifts.

A.2.4 Cycle Time and Availability

The vendor must provide cycle time estimates at 100% efficiency for the parts they have selected to be produced by the robot cell.

In addition, production outputs should be determined based on the batch sizes and overall volumes identified in Section A.2.1. The target availability for the system is 85%. The production output calculations should include 15% down time due to maintenance, fixture changeovers, and so on.

A.2.5 Welding Equipment

The customer will accept recommendations from vendors in relation to the most appropriate welding equipment for the robot cell. Vendors must ensure that all welding equipment proposed is capable of meeting the power output and duty cycles envisaged for a system of this type and the assemblies and production rates proposed.

The welding equipment should include the capability to weld the material for the assemblies selected. If an equipment changeover is required between assemblies, from steel to aluminium or vice versa, the proposed method of changeover and the time required to perform this must be identified.

A complete welding package must be offered, including torch mounting, torch cleaning, antispatter spray, and wire cutting. Additionally, recommendations on wire delivery, reel or bulk pack, would be welcomed.

A.2.6 Controls and HMI

An operator panel will be provided, mounted at a convenient position adjacent to load/unload area. This is to provide all the functionality to operate and maintain the system, as well as to recover from faults. The minimum functions to be included are:

• Assembly/program selection

• System start

• System stop

• Emergency stop

• Fault location indication

The control system will also provide production management information including:

• Number and type of assemblies produced per shift

• Cycle time

• OEE

The system is also to include a down time log, with time and date, including the cause of the stoppage and the time down until the fault is cleared. This is to cover the main elements of the system, for example:

• Weld equipment fault

• Robot fault

• Stoppage due to lack of product

• Stoppage for cleaning/preventative maintenance.

The robot and/or control system is to include the ability to backup and reload programmes. They are also to have suitable, tiered password protection to prevent unauthorised changes to programmes or settings and records.

A.2.7 Enclosure

The enclosure will be constructed from steel panels with appropriate viewing panels. It must ensure no access is available to the automated equipment during operation. Simple and safe access, using appropriate interlocks, must be provided to all areas of the system to clear problems in the event of a fault. The enclosure will provide protection from the welding arc to both the operator and other personnel in the vicinity of the cell.

The cell must operate at a noise level below 80 dB at 1 m when in automated continuous operation. If the process is generating noise above this limit, the enclosure must include suitable sound suppression to reach the desired limit.

The enclosure will include a fume hood over the welding area, with appropriate lighting. The fume hood will include a suitable port to allow the customer to connect to ducting to remove weld fumes from the cell.

A.3.1 Free Issue Equipment

None.

A.3.2 Safety

The design and manufacture of the automation system must be in accordance with the current safety legislation (see Section A.4.6). When operated and maintained as specified in the documentation (see Section A.3.13) and the training (see Section A.3.14) provided by the vendor, the system must be safe. It must also be safe for any other personnel and untrained operators who may occasionally either use or be within the vicinity of the system.

A.3.3 Services

The customer will provide the following services to one location, to be specified by the vendor, within the vicinity of the system:

• 415 V, three phase

• 24 V dc

• Compressed air, 70 psi

Please note it is the responsibility of the vendor to ensure that the air and power supply have the cleanliness and stability required for consistent and safe operation of the automation system.

A.3.4 Project Management

The vendor will appoint a Project Manager who will take responsibility for the project and liaise with the nominated representative of the customer. The Project Manager’s name and contact details will be provided to the customer on acceptance of the order.

A kick-off meeting will take place, within 14 days of order acknowledgement, at the customer and will include the Project Manager, the project team (including representatives of any major subcontractors), and the customer team. This will establish the project aims, schedules, and communication channels and confirm project timescales and the critical path.

Within 7 days of the kick-off meeting, the Project Manager will issue an updated and detailed project timing plan.

The Project Manager will be responsible for the vendor fulfilling its obligations within the contract timescale, including:

• Project planning

• Project resourcing

• Quality control

• Project monitoring

• Subcontractor control

• Customer communications

• Change control

A.3.5 Design

The mechanical design will be developed using appropriate CAD tools and reviewed with the customer prior to manufacture.

A Functional Design Specification (FDS) will be produced for the system and the functionality reviewed with the customer prior to manufacture.

The reviews with the customer are to include a specific review of safety with the customer’s Health & Safety staff.

Approval of the design by the customer will not include any acceptance of responsibility for the performance of the equipment, which will remain the sole responsibility of the vendor.

A.3.6 Manufacture and Assembly

Following design and design approval, the manufacturing and assembly will commence. Bought-in items will be procured, mechanical and control system manufacture will commence, and software will be produced.

All assembly work will be carried out at the vendor’s premises or, if at an alternative site, the location must be disclosed to the customer. The customer reserves the right to view the manufacture and assembly at any stage subject to the provision of reasonable notice to the Project Manager.

All work and manufactured equipment including software must comply with current regulations (see Section A.4.6).

A.3.7 Pre-delivery Tests

Upon completion of manufacturing, the system will be brought to a stage where its functional operation can be satisfactorily demonstrated. The customer will deliver a quantity of parts for the relevant assemblies to the site, based on timing and requirements agreed upon with the Project Manager, to enable the vendor to test the operation of the system.

The vendor will then carry out Factory Acceptance Tests (FAT) to demonstrate the system performs to the required specification. The customer will be invited to witness these tests. Details of the tests will be provided for the customer’s approval, in the form of a Functional Test Specification, prior to the tests being performed.

The FAT will include a preliminary inspection of the equipment and documentation in line with the User Requirement Specification. This will be followed by functional testing as defined in the Functional Test Specification, which will include operation of the cell for a continuous period.

During this period, 5 units of each assembly will be produced, and on completion of these 5 assemblies, the fixtures will be changed. The cell will then continue with the 5 units of the second assembly, until all the assemblies to be produced by this cell have been tested. The Vendor will be responsible for the loading and unloading of the system for these tests.

During this test, the following information will be recorded for each variant of assembly produced:

• Cycle time for each assembly produced (CT1, CT2, CT3, CT4, CT5)

• The length and cause of any down time (DT)

• The time required to perform the fixture changeover (FCT)

A.3.8 Delivery

Once acceptance tests have been satisfactorily completed, the equipment will be ready for despatch and delivery arrangements may be made.

The vendor will be responsible for returning to the customer, at their cost, the assemblies produced as a result of these acceptance tests, together with any unused parts.

A.3.9 Installation Requirements

At an early stage in the project, the vendor will conduct a site survey. The purpose of the survey is to check the floor, confirm building dimensions and the positions of adjacent equipment. It is not envisaged that any foundation work or floor modification will be required, but it is the vendor’s responsibility to notify the customer of any requirements early in the project.

The vendor will produce layout drawings confirming the proposed position of the equipment. The vendor will also indicate the required position for the services (air and electricity). These must be approved by the customer prior to delivery.

A.3.10 Installation and Commissioning

The Project Manager will provide a clear written “statement of works” for the installation of the cell, including a safe system of work, having undertaken a risk assessment beforehand. The installation plan will also identify the number of personnel involved, any assistance required from the customer and also any specific requirements that may interrupt existing production.

The vendor’s engineers will install the equipment at the site. The customer will provide a fork lift truck and driver to assist with the offloading and positioning of the equipment.

The vendor’s personnel will work strictly in accordance with Contractors’ Site rules and Health and Safety rules in operation at the customer. It is the responsibility of the Project Manager to ensure all personnel working on or associated with the project are made aware of the necessary safety requirements. The vendor will be responsible for providing suitable PPE for its personnel and subcontractors.

A.3.11 Final Testing and Buy-off

Once the system has been commissioned, the Site Acceptance Test (SAT) will be carried out to confirm compliance with the specification. The equipment will be formally taken over when the SAT has been successfully completed.

SAT trials are expected to take place within two working weeks of the completion of commissioning at a date to be agreed upon by both parties. If the vendor is prevented from conducting these trials within this period, through no fault of its own, then take-over will be considered to have taken place, and the customer will accept the equipment by default.

The vendor will provide standby cover with one engineer to remain on site for 5 working days following the completion of initial SAT. The engineer will not be required to operate the system but is to offer assistance in the event of problems or breakdowns.

A.3.12 SAT Procedure

The initial SAT will include a preliminary inspection of the equipment and documentation in line with the User Requirement Specification. This will be followed by functional testing as defined in the Functional Test Specification (see Section A.3.7). This will be similar to the FAT but will produce complete batches of each assembly variant (see Section A.2.1).

During these tests, the following will be recorded for each variant of assembly produced:

• Total operating time (TOT)

• The length and cause of any down time (DT)

• The time required to perform the fixture changeover (FCT).

The customer will provide personnel to load and unload the system under the supervision of the vendor.

A.3.13 Documentation

All equipment should be designed to be easily maintainable.

An ‘as built’ documentation package will be required, including:

• CE marking

• Electrical drawings

• Complete software listing including comments

• FDS describing the operation of the system

• System certifications

• AutoCAD drawings

• Full list of commercially available bought-in items together with their source and the reference number recognised by the source.

An Operation and Maintenance Manual will be supplied with the system. This will contain instructions for safe use, as required by the EEC directives and Machinery regulations. This will also detail fault recovery procedures and specify the recommended preventative maintenance including the procedures and required frequency. Details of recommended spares and consumable items are to be included in the manual. The Operation and Maintenance Manual will be supplied in the form of a 1 off CD.

A.3.14 Training

The customer fully recognises the importance of appropriate training tailored to its specific requirements. Our experience shows that a smooth handover of equipment can only be achieved if all users and supervisory staff are properly trained.

The proposal should include appropriate training, to take place before the SAT. This is to include training for four operators and two technicians. The technicians are to receive training on robot programming and maintenance, as well as training dedicated to the cell, including preventative maintenance, fault finding and error recovery. The proposal should detail the training to be provided.

Hands-on training is to continue during the one week of standby cover.

A.3.15 Spares and Service Contract

The proposal must identify an appropriate level of spare parts recommended for purchase. The final list of spare parts will be detailed by the Project Manager and the customer once the installation has been completed. Wear parts must also be highlighted, and the proposal is to include the supply of sufficient parts to operate the machine for 6 months on a two-shift basis.

The proposal is to include the offer of an appropriate service contract. This must include, at a minimum, annual preventative maintenance but may also include other options such as breakdown callout.

A.4.1 Contacts

The main point of contact at the customer for this project will be:

Name

Job title

Address

Telephone number

Mobile number

Email address

A.4.2 Clarifications

Any request for clarifications should be made to the contact identified in Section A.4.1. All clarifications must be confirmed in writing, with email being acceptable.

A.4.3 Environment

The environment is typical for a fabrication facility. The vendor must check the facility and proposed location for the system and identify any concerns it may have early in the project.

Although the system will be situated in an enclosed building, it may be exposed to temperatures below 0 °C when the facility is not working.

A.4.4 Preferred Vendors

The customer uses equipment from the following preferred Vendors:

• Pneumatics – XX

• Electrical – XX

• PLCs – XX

• Motor and Gearboxes – XX

• Welding equipment – XX

A.4.5 Warranty

The warranty period is to be 1 year from the date of successful completion of the SAT. The warranty is to include the replacement of all worn or damaged parts and all the time required to fit and restart the system including travel time and subsistence (excepting where neglect or misuse has occurred). Wear parts previously identified by the vendor (see Section A.3.15) are excluded from this warranty unless unacceptably fast wear has occurred. In this case the vendor will be required to investigate the cause and provide remedial action under the terms of the warranty.

A.4.6 Standards

The system and equipment must meet CE requirements conforming to all the relevant standards, including the Machinery Directive 2006/42/EC, Low Voltage Directive 2006/95/EC, and EMC Directive 2004/108/EC.