Replicator spare parts: the implications - part…

They say 'imitation is the greatest form of flattery', but when it comes to safe, long lasting and efficient operation of your slurry pump, imitations don't get you far.

Replicators are a serious issue in the mining industry; for Weir Minerals, for other solution providers around the world, and for you, the operators.

Warman® slurry pumps are highly-engineered by industry leading experts and developed in state-of-the-art design, manufacturing and test facilities to deliver you exceptional performance.

The strength of our Warman® slurry pump range lies in the superiority of our advanced hydraulic designs and our high performing wear and corrosion resistant materials. This advanced technology is impossible to replicate and when done incorrectly, can have major negative impacts on your slurry pump.

We think it's important for end-users to truly understand how replicators operate and their processes. The fundamental question is: How do replicators create spare parts to fit Warman® slurry pumps?

Reverse Engineering

Most replicators produce their spare parts through the process of 'reverse engineering':

• The replicator purchases or obtains a genuine spare part
• They take measurements of the part and use these measurements to create a drawing from which tooling, moulds, patterns and so forth, will be made
• In some instances, the replicator foolishly attempts to make tooling and moulds directly from a genuine spare part

The machines used to carry out reverse engineering vary from replicator to replicator. The advent of new low cost 3D laser scanners is making it easier for replicators today. However, a parts supplier using scanning devices does not mean it will be able to provide an optimal part. The OEM has a far more intimate knowledge of the part requirements and how it affects other components with the system. This understanding allows the OEM to optimise component design and manufacturing processes.

Restrictions of Reverse Engineering

Despite the availability of high-tech hardware and software to aid reverse engineering, there is an absence of knowledge in the following fundamental areas:

• Optimum tolerances for hydraulic and structural performance
• Material properties to meet wear, corrosion and structural requirements
• Methods of manufacture that will maintain required tolerances

Tolerances

Slurry pumps from reputable OEM manufacturers are hydrostatically tested to verify the pump and ensure the component design meets structural requirements as stated by the design specification.

Proper tolerance on the engineering dimensional drawings developed by OEMs, guarantees that the replacement components meet the correct criteria. This is something which cannot be replicated, and if the parts do not adhere to the required tolerance, this can cause significant problems for the slurry pump.

Tolerance is defined as the amount a dimension or feature of a component is allowed to deviate from the nominal. To adequately convey the requirements for a component, design engineering drawings often utilise geometric dimensioning and tolerancing (GD&T). GD&T is an internationally recognised standard used to communicate the size and relationship requirements of a parts design features.

For example, figure 1 shows a standard dimensional tolerance which only controls the diameters of the component. The relative position is not controlled, therefore improper set up and machining could result in parts that measure within tolerance but that will not function properly. Measuring a part to derive the dimensions for the diameters does not capture the complete geometric requirements. A tactic often utilised by replicators.

Figure 1

GD&T can convey the full design intent and ensure that the manufacturing process selected will result in a component that functions properly. Furthermore, GD&T clearly communicates to quality assurance and inspection personal what variations are allowable.

Using GD&T, figure 2 clearly and explicitly defines the requirements and allowable variations.

Figure 2

Multiple fits and relationships exist between the components of a slurry pump. A thorough knowledge of the design requirements is necessary to ensure that the GD&T for the various components sufficiently controls function, fit and performance, and does not result in interference or poorly mating components. This poses a major problem for the replicator as they are ultimately flying blind.

The complexities and variables behind reverse engineering makes it highly unlikely that replicators will produce an exact replica required for a successful fit-up, satisfactory hydraulic performance and acceptable wear life.

Materials

The next challenge replicators will face is the difficult task of creating the right materials for the slurry pump.

Slurry pump wear parts are made from a range of materials, specially developed for the specific application. For Warman® slurry pumps, all material specifications are exclusive commercial secrets, known only to Weir Minerals and its licensees: often bearing a registered trade mark or trade name or indeed being a patented alloy or elastomer.

Replicating these materials, from just a sample of material, is an impossible task.

It is not enough to simply measure the bulk hardness or carry out a chemical analysis. A material's resistance to wear, corrosion and impact, is a result of proper matrix and the size and distribution of carbides. Elastomers require the proper resistance to common process chemicals and the correct combination of tear and tensile properties. Proper chemistry and proper manufacturing methods are required, and a combination of factors must be taken into account:

Typical considerations are:

• Chemical composition
• • Purity of the base materials
  • Consistent grade and source of base materials
• Methods of manufacture
• • Heat treatment of metals
  • Cure of Elastomers
  • Location of chills for alloys
  • Type and quality of stabilisers for elastomers

Manufacturing Methods

The manufacturing methods and processes used by Weir Minerals have been developed over many years using expert engineering solutions. OEMs know their products inside and out; they know what works and continuously make advancements to improve their technology.

Production facilities required to manufacture genuine spare parts using advanced materials are highly sophisticated and employ very expensive machinery. It is unlikely that replicators would have the equipment or the knowledge to satisfactorily machine these specialist materials.

Taking into account the necessity to match optimum tolerance, the correct material properties, method of manufacture and the high cost of good quality tooling, the chance of achieving anything like the overall performance of the OEM part is low.

Our Warman® slurry pumps did not become the market leader by coincidence; it is a result of years' of commitment to the development and advancement of slurry pumping technology. Knowledge and expertise that replicators do not have and cannot imitate.

Problems experienced from replicator parts

Fitting non-OEM spare parts brings a range of problems. Common problems end-users around the world have experienced with replicator parts include:

• Poor hydraulic performance
• Poor wear life
• Damage to adjacent genuine parts
• Dimensional errors that prevent pump assembly

This, in turn, has a negative effect on users' total ownership costs:

• Increased maintenance costs
• Decreased plant productivity
• Increased energy costs
• Delayed rebuilds and restarting of pumps

There are many implications with replicating genuine spare parts, presenting an array of consequences to mine sites across the globe.

In the second entry of this two-part blog series, we examine the consequences of using replicator spare parts and the detrimental effects they have on slurry pumps.

Follow the link for part 2: the consequences

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