Industrial Technologies

Industrial Technologies Prof. Marco Macchi A.A 2016/2017

Introduction to production systems

First of all, it is necessary to define clearly the meaning of:

Production is a process, a list of scheduled activities that are required to produce goods or services delivered to the market by a company. The action of creating something, realizing goods in any different way like primary production (chemical, cement industries) or assembling components. It is a sequence of activities to transform the material into a finished product. The activities’ sequence can be represented by an ASME diagram.

Production system = a subsystem of the company. It uses resources as inputs – raw materials, semi-finished goods, energy, information, knowledge, … - to provide products and services in order to satisfy the customer needs and the objectives established by the company’s strategy. The inputs must be organized in an effective and efficient way to generate outputs throughout several transformations. Finished goods will be sold to generate profit. The output may be a physical good or a service.

Production plant = physical plant, industries, laboratories, real spaces in which the production system is established. The physical space in which machines are collocated. This space should be accurately designed to optimize the WIP flow along the transformations needed by the process. This will be one of the purposes of the course: becoming able to create an efficient scheme and plant of a production system.

Factors represent inputs of the process (material acquisition, data retrieval); production process is the phase in which transformation takes place, the phase for creating; product/services is the final part of the process concerning the sale of the goods and the generation of customer satisfaction (distribution). A production system is a set of assets that implements, through an industrial technology, the production process.

Logistic is the science that comprehends all these three activities while production refers only to that phases that are normally held inside the company (especially for manufacturing companies that dislike to entrust somebody else to produce finished goods because quality of finished goods is often the main competitive gap between competitors and no company would like to advantage the others with phenomena such as spilling over) or delivered in outsourcing but represent that part of logistic in which things are created.

The image below shows how production may be represented at the intersection of two processes. The creation of a new physical good, for instance, requires first of all a deep analysis because market managers must research and satisfy customers’ tastes with new ideas or new products. So before launching a new item, it is necessary to discover or imagine how the market can react to this newcomer. It’s required to pay particular attention to cash flow analysis, evaluating this new possible investment with long-term objectives measurement in order to take care of investments cost and estimate future incomes and revenues. If the market analysis response is positive, designers and engineers should start thinking about the new product, its physical appearance, and how it should work. Then it’s also necessary to create an efficient and obviously a functional production process and production plant too. Meanwhile, before starting to sell, logistic operators should have begun to contact and select the best supplier for raw materials and have created a valid distribution network to reach all the customers according to the company objectives.

Describing production processes – ASME diagram

Production processes are multi-stage processes: it means that a sequence of operations are required to realize the process that allows obtaining a product from raw materials/components (e.g., a rotating shaft from a steel bar through various machining operations; a plastic bottle from a series of chemical or physical transformations; a car from car body, engines, and other parts). The sequence of such operations is described in a process diagram representing the technology cycle. To do so, the American Society of Manufacturing Engineering (ASME) has created a global language made of symbols.

The control step usually is at the end and in this phase the result obtained is compared to what has been planned in order to generate a measure of performance and understand how the company has worked efficiently. This is the main reason for which planning is so precious, because it helps managers to discover non-efficiencies.

There are different types of production flows:

• Synthetic: It starts from at least two components that converge in a unique process; e.g., the assembly phase.
• Analytic: It is the case of refineries, starting from crude oil we can obtain different products according to different processes.
• Combined: Comprehends both synthetic and analytic processes.

Technical drawings

Represent the relevant features of the final product. It is from an engineering point of view.

List of parts – Bill of materials

It is from a managerial point of view. There is a graphical representation that shows how the different parts are assembled in the final product. Two kinds of information are needed: kind of components and number for each component (it is possible to have the bill of material also in a table form).

Cycle times/Production programs

Cycle time sheet: the final output is the total amount of time for each operation; it works as an input for the design of the process. The important parameters for the specific type of the process are technological parameters: cutting speed and feed rate. We have to translate technological parameters into time requirements that work as an input for the process design phase.

The production capacity is the time we need in order to produce that specific element on that specific machine to satisfy demand. The cycle time gives the order and the time per each single transformation of the process so that we can theoretically understand how the entire process is structured, the flow of transformation, machines, and resources involved and how does the production process last. Theoretically, because we are considering that everything will proceed in the right way, and in times scheduled, but practical experience teaches that there may be several issues like breakdowns of machines for instance.

The production program usually is given to the operator together with the instructions: production program/work order.

Flow sheet of a production plant

The flow sheet is helpful to get an immediately visual understanding of the whole process. It’s not a standard language but it is quite common, used to have an overall look of what is happening. It’s often used by energetic engineers to explain how gas or liquid work and circulate in rotary engines: different phases are linked by an arrow. Through the flow sheet, it is possible to visualize both vertical and horizontal flows; it is a graphical representation of the production system, through a map that resembles the real equipment (possible also with symbolic representation).

Layout of a production plant

The plant layout is a schematic layout (approximated representation of each area) or a detailed layout (we know with precision where the resources are located – detail of the different resources in each department). It is a map, usually a virtual and visual description of the physical places where activities take place. It is really important for designing and eventually remodeling plants.

Type of production technologies

A production system is an arrangement of resources necessary to sustain the process (e.g., beer brewery: industrial process, only in the last phases you see the discrete phase). The technologies that can be used are of different kinds.

Types of production system

The classification of production systems is based on:

• The production strategy
• The production process, volume, and demand
• The configuration of the production system

Wortmann Classification

Companies are put in different classes according to their way of reacting to external stimulus. I mean customers make orders and industries may be classified on the way they react to these orders. A company operates between suppliers and customers, they need to be efficient in the way they collaborate with suppliers and in the internal performances but also effective towards their clients. According to these different behaviors, enterprises are divided into five classes. Their behavior as I mentioned before depends on the condition of the market in which they operate.

For instance, in a global mass market like the food market (pasta), customers expect to find products immediately on supermarket shelves without ordering them. This kind of solution forces industries to fill shelves before selling any goods based on production and distribution only on accurate forecasts – MTS (made to stock – production). On the opposite, we can find the ETO system (Engineer to order – Ferrari, Fincantieri). In this case companies wait for the orders and then begin to develop a new plan according to the specifics of the client. We can guess volumes of production are lower than those in the MTO system but of course involving more phases of production and usually being big projects, those processes will be much profitable. In the middle, there are other possible configurations that companies usually adopt managing the trade-off between efficiency and effectiveness.

Abel Classification

There are 3 different dimensions to classify industries:

• Demand: How the company reacts to the market and replies to the orders; how it answers the market and works inside.
• Process: How the product is realized; two are the main processes:
  • Process industries/primary industries: They produce large volumes of raw materials or goods like oil or cement in a continuing way.
  • Manufacturing plant: They can produce components for other companies or processes or they can assemble them to realize a finished good to sell to customers.
• Volume: How many goods are realized per time. A single item, batch production of different items, or continuous production.

Production system KPIs and costs

Performance measures and costs are both relevant (some costs are fixed and some others are not).

How production systems work

A production system is a group of different resources that are ordered and scheduled in a plant. Implementing a production process, in order to do the different activities, resources are used; resources, moreover, can be at different states.

Machine

A production machine could be in different statuses, working or blocked (idle) because of several reasons:

• Working
• Under maintenance/repair (corrective)
• In setup/change over
• Waiting (idle state) for different reasons (waiting for pieces, for operators, ...)

For example, we are preparing, arranging resources (raw material, WIP, operators) to realize that kind of production activity, resources like tools needed by that specific process. All these operations which prepare the machine to work, I mean cleaning the machine and setting the resources needed are called setup. Machine may also be blocked due to their monthly maintenance or let me say periodic reparation in order to avoid any kind of drastic brokerage that may cause a huge loss of performance and deeply impact on the firm profitability. Sometime machines do not work because they are waiting for some resources missing like operators or raw materials: these are logistic troubles that may affect their productivity. Obviously, in the worst case, they may be broken too (think of using a particular tool not allowed to work properly on a machine: it is probable it will break and cause a damage to the machine and to the process). It is important to know this possible status because we will design the system and so it is remarkable of paying attention to any kind of problem that may affect its right way of working.

Operator

An operator could be involved in different operational tasks:

• Working on a machine/system (e.g., manual assembly station)
• Monitoring and supervising production
• Performing quality checks
• Preparing the machine (setup), e.g., hanging tools, cleaning, loading materials, …
• Loading/unloading materials
• Doing maintenance/repairing machines

From managers’ point of view, operators represent resources and so our objective is to dimension their job, organizing their work (for example by deciding whether they have to work during the night or during the day if the company works 24 h/day). They can be multi and over-skilled and do a large number of activities like preparing and realizing the physical transformation of products or monitoring and supervising the whole production process: today this role is quite common because of the deep automation of processes. Nowadays companies’ processes are commonly rich of technologies in order to reach high volumes of production and high performances permitting companies to reduce their price and afford cheaper goods to customers. In this case, operators become controllers they check the quality of the processes.

Raw materials

Raw materials will be processed and will change the status in which they are.

Tools

Machine tools are computerized; CNC – computer system that controls the machine’s operations. Tools have their own status as well – working in a machine.

According to the state in which resources are, we can make measures. We have to be clear on the way production is arranged. The company receives some orders from customers and these become work orders (or production orders, manufacturing orders, job orders). Job orders are planned and scheduled in the production plan according to the importance of the order and due to the relevance of customers and obviously due to the moment in which they were made. Then job orders are “launched” and executed. Modifications in the production plan could happen (changes in priority, problems, …). Work orders are moved in the production system according to the technology/process cycle. We can immediately point out that production system must be designed taking flexibility in account that is the capability of being flexible. It means the capability of briefly change and adapt to changes and modifications that were not scheduled. Flexibility is the main characteristic of a production system. Production may be organised in different layouts, each of them with its own benefits and disadvantages; flexibility is, of course, included in these considerations: there are particular configurations that assure much flexibility than the others like job shop rather than transfer lines (rigid system) for example. It all depends on what we are searching for: we have to correctly and coherently shape and design a production system in order to fulfil our needs.

A production system is organized with different layouts and its resources are normally grouped in departments or production shops according to different bases and purposes. The entire list of production resources is normally addressed as shop floor (in Japanese this is said “genba”). Obviously, different layouts will guarantee different performances in production and it is up to companies to decide what configuration to choose. Layouts differ in terms of production volume (e.g., number of products) reachable in the amount of time and product variety (e.g., number of different types of products).

The following histogram shows a good correspondence between volumes of production and customers’ likelihood. Where demand is enough, it will be required a system which can produce high volumes in a continuous way. On the other hand, when demand is scarce company should decide to produce less and organized production in batches for example.

Performances of production systems

Performances are a way of measuring how a system usually works. We would like to measure how a system works in terms of quality, flexibility, rapidity and so far so for. The main operational performances are:

• Lead time (throughput time, flow time): Duration of time required by the work order, from start of production to finish [hours, minutes, seconds]
• Set up time: The time it takes to setup a production equipment for processing a new work order [hours, minutes, seconds]; we should understand which machine is the most rapid or flexible to correctly predict our productivity
• WIP – Work in Progress: The amount of inventory that is being processed or is waiting on the shop floor [quantity of work orders, or space occupied by the material]
• Production rate (throughput, rhythm, production capacity): Number of products that a production system is able to produce in a time unit [piece/h, products/day, ...]; It is the speediness of a system
• Cycle time: Is the time period elapsing b/w the exit time of the precedent work-piece and the exit of the successive work-piece from a system, it is the inverse of a production rate [time/piece].

The concept of lead time

The total lead time of a job order is the time that goes from the receipt of the customer order and its fulfilment. In other terms, the time corresponding to all internal activities belonging to the company supply chain to physically realize the good and then deliver it to its acquirement. It is the time that is necessary to perform all the activities inside the factory from the customer order arrival to the moment in which the material is ready to be delivered. As we can notice, there are lots of different lead times including those such as release of production order and acquisition of the order, inspection and final control, storage, etc. So the production time is not entirely “productive”: production activity is composed of several phases, for example, fabrication, setup, control, etc. each of them requires a certain amount of time. We are simply splitting the production lead time in other sub-lead times that belong to this one in a hierarchic way.