7 Questions on Manufacturing Process Systems: Choosing Your Next Mixer or Dryer

• Selecting a powder process mixing or drying system takes a unique approach that we call a capital equipment purchase mindset. 
• To get into this mindset, buyers can ask themselves seven questions that help define, focus and quantify technical information that will drastically improve vetting and qualifying manufacturing process system options. 
• The best process system purchases are governed by a robust purchase agreement that outlines every critical factor in clear, actionable pass/fail metrics that can be tested and commissioned against.

As a leader in industrial or manufacturing processes, you spend your days thinking from an operational perspective. Contemplating production effectiveness, quality controls, demand forecasts and so on keep you occupied right up to the moment when a new capital project hits your desk. When such projects include equipment upgrades or complete new systems (such as industrial powder mixers or dryers), it’s time to switch from an operational mindset to a capital equipment purchase mindset. 

A capital equipment purchase mindset is specification-driven: It frames an application in terms that an equipment supplier can directly measure against. This helps establish a starting point for your discussions with prospective equipment vendors, putting tangible data points and performance expectations front and center. 

We find that many operational leaders appreciate a framework for switching over to the capital equipment purchase mindset, so we share that here. 

7 Questions To Ask When Choosing Your Next Process Mixer or Mixing Dryer

To start thinking from a capital equipment purchase mindset for a powder mixing or drying project, you must first recognize the core goal: to turn your operational wants, needs and desires into finite technical design criteria that equipment vendors can guarantee and warrant back to you in the form of an equipment purchase agreement. 

Here are seven questions to help organize your thoughts: 

1. What industry- or application-specific criteria govern the project? 

Powder and mixing applications can be found in countless industries, spanning a very wide range of styles, designs and product types. For this reason, it’s best that you begin with a clear understanding of the narrow industry or application you’re shopping for, which limits the potential vendors and technologies down to just those qualified for your project. 

Further, naming the industry or application inherently invokes pre-established standards to the project, such as acceptable materials of construction, governing code compliance, hazard and safety management methods, and specialized attributes (i.e. hygienic design for food products).

2. What are the physical properties of each ingredient? 

While an operations mindset tends to focus on finished products, an equipment purchase mindset looks just as closely at the incoming ingredients. You’ll want to round up ingredient profiles that include particle dimensions, bulk densities (for powders) and specific gravities (for fluids), viscosities, chemical properties, and functional characteristics (such as hydration rates and flowability). 

In addition, you’ll need to establish ingredient proportions across all of your recipes, so that manufacturing process systems are designed to handle both minimum and maximum volumes.  

3. What are the physical properties of the end product? 

As we mentioned, the end product’s properties are just as important as incoming ingredients. Here, you’ll gather critical physical criteria for your end products: bulk density, moisture content, particle size, texture, and even color and sheen are common properties of interest. 

By specifying these finished product details, the equipment manufacturer can expressly determine their mixing process, solving for turning the above ingredients into your required finished product state. Also just like above, you’ll want to specify acceptable and unacceptable ranges for each key property, thinking about future acceptance testing and sign-off. 

4. What mixing method or technique best suits your product?

While the equipment vendor will determine their mixing process as a function of turning ingredients into a finished product, there are additional considerations that your experience with your products will prompt. 

For example, you might know that your powder’s high dairy fat content responds negatively to moderate shear, or that your wastewater sludge requires a degree of back-mixing to deter stickiness. You might also have brand or labeling requirements that drive specific solutions, such as “sustainable production” that calls for the use of a vacuum dryer with solvent recovery.

5. What are the physical or analytical target values of the mix?

Here is where you can truly set yourself up for success at the end of the equipment purchase engagement. By specifying the physical and analytical targets of your end mix, you’re not only clearly defining the most important factors of your product that equipment must be designed to replicate with every batch, but you’re also providing the testing requirements that you will use upon commissioning to accept the equipment.  

In this way, carefully selecting critical analytical targets has both a performance and contractual impact. We commonly see analytical test targets of apparent density, moisture percentage, spectrometer composition, sieve size distribution analysis and flow testing. Often, better analytics are worth higher equipment costs, especially when those analytical values represent your customers’ main buying points. 

6. What are your batch or continuous mix parameters?

With this question, you’re thinking about how new mixing or drying equipment will balance production volume demands, product quality and capital costs. For example, you could reach a required 10,000 pounds of product per day by producing five 2,000-pound batches, two 5,000-pound batches or running a 2,000 pounds per hour continuous production system for five hours. 

Batch systems are great for flexibility across many products, whereas continuous systems are better for high volumes of one or a couple products. As volume or rate increases, capital costs tend to go up while operating costs tend to go down (relatively). As volumes or rates decrease, capital costs tend to go down and operating costs go up (relatively).      

7. How accurate, repeatable and controllable do mix results need to be? 

Accuracy and repeatability are two measurements of equipment performance that you should quantify for your project. 

Accuracy relates to precision, and is typically expressed as a permissible error: For example, +/- 2 percent accuracy of total batch mass means that a single batch will fall within +2 percent or -2 percent of the target batch size. 

Repeatability measures the expected deviation range between batches or runs: For example, +/- 5 percent batch mass repeatability means that multiple batches will all fall within +5 percent or -5 percent of each other over numerous runs.    

Controllability refers to the size of units the system can discern: For example, “controllable by 100 gram increments minimum” means the system cannot accurately measure values in less than 100 gram portions.    

Tighter tolerances for all these values are usually perceived as better, though are accompanied by higher costs.  

Returning to the Operational Mindset

Now that you’ve quantified your requirements in a way that equipment manufacturers can most readily quote against, you can put back on your operations hat. At this point, you’ll likely be filled with operational questions that you had kept at bay, and it’s OK to let those flood in. 

Is maintenance on a potential mixer or dryer easy or difficult? Are the controls user-friendly? Will operators need special training or ongoing certification? Let yourself run wild through these questions, and pick out the ones that you know need to be integrated into your purchase agreement. 

So long as you remember to frame every question as a definitive specification that can be quantified, measured, physically tested and assigned as a contractual obligation, you can be confident your new manufacturing process systems will be designed to your exact needs.