The 5 things to know when you need to build or modify your mixing plant (and that the manufacturer will never tell you)

silos polveri

When you have to choose who will build the new mixer feeding system or who will modify your old plant, you are faced with a real dilemma because you can’t really afford to make mistakes.

This article wants to give you the real useful tools to be able to make the right assessments  to choose the company that best suits your specific needs and avoid mistakes that could cost you dearly.

How to avoid errors in the selection of the mixing plant manufacturer

It is not true that the most structured manufacturer is always the best choice, just as it is not true that the small company should be discarded because it is small.

It depends on what you have to do.

The following tips apply to all builders and will put you in a position to not make mistakes.

Here are the 5 things you should know before choosing who will put their hands on your system.

1.     Analyze the preliminary diagram in depth

If you need to create a new system for transporting and dosing products to be loaded in the mixers (both for rubber and plastic), the first thing to evaluate is the type of products that must be treated and the quantity of the same that must be transported and dosed every hour and for each shift.

This information combined with the technical data sheets of the products and the type of supply of the same (Big-Bag, bags, cisterns, other) are the first documents that you have to share with the manufacturer before they start working on the diagram.

This first phase allows you to understand if you are dealing with experienced professionals or simple mechanical companies. Yes but how? Evaluating the completeness and detail of the preliminary diagram.

But be careful: you don’t have to evaluate “by eye” if you like one solution more than another, but you have to do an analysis together with the manufacturer to understand the reason for each choice made, regardless of the price at this stage. Don’t look at the price, not yet.

In this phase you must evaluate:

  • the flexibility that the system allows you
  • how they planned to do the cleaning in case of production change
  • how they designed hoppers and scales to avoid that the product does not fall
  • how they guarantee you the precision in the dosages you need
  • what effective capacity the system can guarantee.

Every manufacturer has his own method and his technical solutions, all of them are correct a priori. What you need to check is if the manufacturer can answer effectively to all your preliminary questions and if the answer satisfies you in full without leaving you doubts.

If any explanation does not convince you or if the seller says “… then we define it at the design stage …” keep it in mind. A prepared and experienced company must be able to respond immediately and without hesitation and must also show you similar projects where the same solutions have been used.

2.      Be wary of those who have no consolidated experience

An important investment like the one necessary to realize a new plant must be evaluated with a very long period of time, at least 15 years.

I know plants that are over 30 years old still perfectly working, of course with the right maintenance and updates.

It is true that, also companies other than the one that build the plant can modify it later, but it is advisable to maintain a relationship with the company who made it, who has all the construction and installation drawings, has the list of the supplied material and obviously knows the producers.

It is therefore important to evaluate the company’s history: for example, how many years it has been present on the plant market; or if before, he only took care of some mechanical work and then threw himself into the installer’s world.

My advice is to beware of those who do not have a consolidated experience or who say: “… we do what the market leader does, but we cost less …”.

Think about it and ask yourself: “If I need them in a few years, will they still be there?”

A good practice, therefore, is to ask to show you plants made recently similar to what you want to do or at least in the same sector. It is not said, in fact, that if I have experience in the transport of flour, I can also transport silica or calcium carbonate.

If you don’t want to have a stomachache you have to avoid making solution tester for them.

3.      Ask the right questions about plant automation

On the subject of automation I should write a book (and maybe I will do).

Many manufacturers, when proposing a system, treat the automation part as if it were a simple accessory, without the right attention on this aspect.

On offers, the description of the automation is often relegated to the description of the electrical panel and 3 standard phrases about the software.

But the type of electrical panel or how big it is or if it contains 2 inverters or 23 motors is NOT important. The electrical panel and above all the software must allow you to carry out all the productions you need. If they have forgotten an inverter and therefore have problems with transport or dosing, it is not your problem, they have to solve the problem.

When a list of cabinet accessories is provided, it is often an excuse to then ask you pay for anything not included that serves to guarantee the performance of the system requested when ordering.

Therefore, if you ask for a complete automation system and you do not have the experience to give precise indications, the great advice I can give you is to ask that the automation be carried out by one of the two or three truly specialized Italian companies in the sector.

Of course you already know one of it ?.

However, the really important things about the automation to ask and verify are:

  • Materials of primary brands only (avoid any card or non-commercial component)
  • For the PLC and the inverter, ask them to be brand leaders only. In our industry: Siemens or Rockwell or Omron. Other manufacturers make excellent devices but they are not widespread in our world (if you need to exchange data with other machines or systems it is easy they have one of these 3 PLCs brands).
  • If the system is very large, ask to have several distributed cabinet instead of a large one. It will cost you a little more but you will have great savings in the electrical system and more easy way to extend the plant in the future. Furthermore maintenance and troubleshooting will be easier.
  • Ask to see the software of a similar project in simulation and analyze how data, recipes, production plan and reports are managed.
  • Ask if it is possible to install the program on several PCs and how the main PC failure (backup system) is managed.
  • Ask how the post-test assistance is organized and whether they have a service contract with certain remote connection times.
  • Important: if they answer one of these questions that “we don’t have it now but we can do it …” be very careful, because it means, also in this case, that you could be the first on which they develop this project.

4.     Assembly and testing: check what is included in the price and what is not

When you arrive at the signing of the contract and ask for the final price, you must pay close attention to the things that are included and to those that are excluded. One of the most important items is assembly and testing.

The best thing of course is to ask for an all inclusive project. In this case, every activity is under responsibility of the construction company and you will pay the final fee only when all is working fine.

As you can imagine this is also the most expensive option. Many activities are carried out by companies outside the main constructor (see electrical system and automation) so they have to take the risk and of course they ask you for a higher price to sell you the services.

If you do not have an important budget and if you already know companies specialized in industrial electrical systems or mechanical assemblies, you can also ask for work supervision only.

This consists in the more or less constant presence of a representative of the plant construction company that directly follows all the works, from mechanical to electrical assembly, to commissioning, but individual local companies are payed directly by you.

In this case you have to pay attention to some things:

  • How many days did they provide for supervision and testing;
  • The costs for each extra day;
  • Who pays the various suppliers in the event of mistakes.

Let me explain: if the contract contains a fixed number of days for assembly and testing, it means that once these days are over you have to pay the daily cost for each additional day.

If the delay is caused by you or the companies you have chosen, it is your problem; but if it is caused by the main constructor that may have had problems during assembly / testing, you may have to pay for faults not only the manufacturer but also all the companies you have contracted directly believing to save.

Once again, the advice can only be to rely on companies that are expert in your field with years of experience behind them and with different projects completed.

There are no particular problems if you prefer this option; however, you must be sure that the companies you choose directly are able to manage the work in the correct ways and times.

5.      Always evaluate the total cost in the medium and long term

Nobody likes to spend more money than strictly necessary and nobody wants to have problems and production losses due to the new plant.

These two things are closely related. When evaluating the investment you do not only have to assess the initial cost of the plant but also and above all the total cost in the medium and long term.

Spending less at the beginning to have problems after few months from commissioning is undoubtedly worse than immediately paying more but being quiet and producing for years without difficulty.

As in all sectors for the same plant you could find very different prices.

It depends not only on the level of materials used and the finishes but also and above all on the level of engineering and the reputation of the manufacturing company.

Also in this case, the advice, before proceeding to the evaluation of the price, is to expect to see similar systems to yours to make sure of the level of construction, completeness of the software and actual competence of the manufacturer.

If you have several companies that you consider suitable, make a comparative table by assigning a score to each item: you can choose the company that will have the best score.

And you can always negotiate the price to get the best deal on the condition but avoid exacerbating the economic negotiations seeking discounts impossible. The risk in this case is to put in difficulty the manufacturer who, to take the job at your price, could compromise the reliability and performance of the project in the long run.

And in the end forcing you to spend more money anyway.

I hope this guide is useful to you.

However, I remain at your disposal to give you every possible advice so that you can serenely choose a strategic supplier like the system builder that will follow you for years.

You can write to me at claudio.tosi(at) or call me at +39 059 537902.

Buona vita

Claudio Tosi

    Claudio Tosi

    Nato nel 1974 a Modena, si è diplomato all'istituto superiore Enrico Fermi in elettronica e telecomunicazioni. Dopo l'anno di militare ha iniziato il suo percorso professionale come tecnico programmatore presso la Multi Data s.r.l. Dopo oltre 20 anni di lavoro, si occupa di seguire i nostri clienti nel settore plastica e gomma, aiutandoli a migliorare la produzione e ridurre errori e costi.

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