The True Cost of Owning a Mill: TCO Beyond the Purchase Price

When it comes to purchasing a new mill, the option that has the lowest cost at the point of purchase is often a very attractive proposition, especially if the project has fixed budgets and saving money where possible helps the bottom line.

The problem with this is not knowing whether purchasing the more affordable option actually turns out cheaper once it enters production use. Purchase price is just the first line in a total cost of ownership (TCO) calculation. A deeper, more explorative comparison is required, one that takes into account what each mill costs but also what its operating & maintenance costs are and what it needs to remain productive across the period a business intends to use it.

For cone milling equipment in particular, that means looking beyond conventional expenditure to examine tooling life, stoppages, and the amount of usable product produced each run.

Here, we’ll show which costs belong in a mill TCO assessment so that engineers and operators have a practical basis for asking suppliers for comparable information.

Why Purchase Price Is Only One Part of Milling Equipment Cost

Total cost of ownership is defined as the financial impact of an asset across its entire working life, not just at the moment it's ordered.

Practical TCO models start with the front-line acquisition cost before adding expenditure and production losses that follow during operation.

A Suggested TCO Formula

Mill TCO = acquisition cost + operating costs + consumables and maintenance + downtime and production losses + end-of-life costs

Two mills that have the same required throughput or particle size objective can have very different lifetime costs. Lower-priced machines only remain the better purchase if their savings are not erased because they cost more to run and require a greater level of maintenance.

The comparison between two, three, or even four mills should be done over the same assumed service period and workload because comparing one machine on its upfront cost and another on long-term performance can produce a distorted result before the calculation has even begun.

Where Does the Lifetime Cost of a Mill Actually Come From?

Consumables, replacement parts and maintenance accumulate one run at a time

It's more than likely that operators want a new production-scale mill to remain in service for many years and over that period components such as screens and impellers will wear and require periodic replacement. These replacements should be treated as recurring expenditure (i.e. included in the TCO).

As well as replacement parts, the mill’s maintenance costs should include the labor required to inspect and service it. A cheaper component may not always reduce the TCO if it doesn’t operate for as long as a more expensive option or if it creates longer maintenance breaks.

The availability of parts matters as much as their price too. If a component critical to production can’t be supplied when it's needed, the associated cost may quickly move from a maintenance expense to one associated with downtime.

Downtime, cleaning and changeovers put a price on lost production time

Repairing parts of the mill is only one of the ways its production can be stopped. Downtime due to cleaning or changeover should be calculated in units of lost productive time rather than being factored into repair spend alone.

Even planned interruptions count, too. If the process requires frequent product changes or more frequent access by operators, these interruptions can all accumulate substantially over its service life.

Those responsible for comparing and purchasing mills should compare how often intervention is expected and how long routine tasks such as cleaning actually take. Doing so will allow them to create a more accurate financial picture regarding lost production time.

A more expensive, modern mill may help to reduce the overall TCO compared to a cheaper alternative if it supports more efficient cleaning routines or quicker product changeovers.

Yield and off-spec material can outweigh a small difference in equipment price

A mill earns back its investment by producing the usable material a business needs to make a product or sell it to those downstream in the supply chain.

For that reason, the TCO should factor in how consistently the feed reaches the required particle-size result. Measuring it by how many kilograms can pass through it per hour fails to consider the effectiveness of the process.

If products require several passes through the mill, this consumes additional machine and operator time that could be used for new, commercially beneficial batches. Further, material that cannot be recovered due to smearing or wedging in the apertures creates an even starker cost.

Here we can see how the process becomes a commercial factor, not just a technical consideration, when it is repeated consistently.

At Quadro, we’ve designed our range of mills around controlled particle size distributions and consistent processing to help those assessing TCO feel reassured that the proposed configuration can consistently achieve the required result.

Energy matters, but it should be calculated for the real process

The energy used by the mill belongs in the TCO calculation because even a small difference in consumption, repeated across hundreds of processes during the life of the machine, can add up.

Buyers need to look beyond the energy used in the mill’s motors and understand the power required to produce the necessary throughput and particle-size result under various operating conditions.

If energy or heat sensitivity are factors in the buying decision, operators should prioritize application-specific test data over general equipment claims laid out in a spec booklet.

How Do You Compare Mill TCO Before You Buy?

When speaking to suppliers, asking them all for the same operating information for a TCO comparison is useful only when every option is being measured against the same job.

Use first-hand plant data where possible, as the value of one hour of downtime, for instance, will differ significantly between manufacturers, meaning generic industry averages can easily obscure the financial issue that matters most to you.

Mill TCO Supplier Comparison Checklist

Build Quality and Supplier Support Change the Calculation After Commissioning

A mill should not be judged by how well it performs when it's new and has been checked to ensure it meets the agreed requirements. Its value to a business depends on how well it can continue to deliver the necessary process over the years the business plans to keep it.

Judging it through this lens makes equipment history, access to appropriate tooling, and ongoing technical support far more relevant purchasing considerations rather than secondary ‘nice-to-have’ benefits.

Since we began developing our Comil^® conical milling equipment back in 1976, the team at Quadro has continued to work with manufacturers to match the mill, tooling, and process parameters to the required outcome.

The TCO value of a mill should be expressed and judged against application-specific evidence rather than a blanket claim that one machine will always cost less to own.

The Lowest-Cost Mill Is the One That Costs Less to Achieve the Required Result

Purchase price should always remain part of the final investment decision. The aim of TCO analysis isn’t to justify spending more but to determine whether a price difference still exists once a mill has been operating for a distinct period.

Where that difference is difficult to establish from a quotation alone, operators should scrutinize application testing and have detailed discussions with the equipment supplier to replace assumptions with evidence.