As it was mentioned in the previous blog, the machine you need to design for your process might already exist in the market in a different shape or form. Therefore, it is a good idea to spend time doing some in depth search at the beginning. This research is necessary as it will give inspire your new machine design even if you end up not finding exactly what you were looking for. However, let's assume you couldn't find anything. What do you do? Where do you start. We will look into that in this blog post. Well, you will need to look at the system specifications firstly.
When the Request for Proposal (RFP) or Request for Quote (RFQ) comes to the engineering and management team, someone somewhere must set some systems specifications, or there will be great disappointment when the machine is turned on. Someone needs to establish things like:
Throughput rates;
The processed product’s size and weight;
How to determine out-of-tolerance products and what to do with them;
Who is responsible to guarantee that the incoming product is within tolerance;
Available electrical and compressed air facilities;
Floor capacity — in weight per square foot;
Floor space available and ceiling height;
Pillars and other obstacles to be negotiated;
Noise levels;
Available entry passage to desired machine site;
Expected machine life — Mean Time to Repair;
Safety procedures at the desired site including relevant ANSI standards and local codes.
Failing to establish these specifications can lead to negative consequences for engineers, such as financial loss and stress. Imagine you design and deliver a machine to customer's site that doesn't fit through their access door. Therefore, it is important to never submit a proposal without a list of system specifications, and also avoid designing or building a machine configuration without them. However, in reality, situations may arise where the process is not followed in that order and adjustments need to be made to move forward.
Brainstorming
Brainstorming about new automation machines heavily relies on one’s experiences and the review of existing machines, and from resources such as this text. However, as has been stated for various reasons above, very few really “new” sections of these machines are designed if at all possible. It would be desirable that a machine builder with great experience looks at their CAD database and borrow a good chunk of many previous machines to get a reasonably optimal performance. The true optimal may be a luxury. They do not want to perform what is usually referred to as “research” as found at many universities. It is too risky and takes too long. So the brainstorming done is usually on the limited side compared to what is often found in new product development. These totally new creative developments have their high costs, where the first unit development costs range from three to 10 times unit production costs.
Brainstorming does happen when a machine builder sees a market need that cannot be addressed with a traditional machine (since many builders often seem to clone each others work anyway). The builder sees the opportunity as a potential for great profits if an investment is made from their internal funds. Or the new concept may come from an independent inventor or entrepreneur who is looking for a partner. We will look into this in one of the subsequent blog posts.
Machine Classification by Function
Traditional automation machine classification is often based either on its primary function or by the form of the material handling system at its foundation. We will review the most common forms here, add some insight into their usefulness over the past 20–30 years, and comment on their potential for the future. There are a wide number of functions that a machine can perform, but if one looks at the history of what has been built to date, and one was to try to classify the significant groupings that would result, several major classifications
would emerge:
Assembly
Inspection
Test
Packaging
Assembly Machines
Assembly Machines as a group can range from the production of a high-volume part such as a spark plug or a piece of home kitchen cabinet hardware, to the construction of a cell phone. Throughput rates and product flexibility expectations can vary. The machine to assemble a J8 model sparkplug most likely can operate for 10–20 years without any required changeover. J8 sparkplugs will live on forever. But the market novelty for a particular model of a cell phone can be six to nine months. Changeover is required if the automation is to be kept from being a boat anchor. And it most likely is not cost justified in such a short timeframe with today’s competition.
Inspection Machines
Inspection Machines are significantly fewer in number than Assembly Machines. Although in-process inspection is currently desired even more, inspection is often performed as an integral operation within the Assembly Machine. Computer vision systems and dimensional measurements are two of the commonly found inspections performed within the Assembly Machine. However, stand-alone Inspection Machines for checking a packaged product for the correct weight (check-weighers) and making sure no metal filing from all of the food processing machines fall into your box of corn flakes (metal detectors) do exist and have meaningful niche markets.
Most of these Inspection Machines generically have a product inflow, a checking station, and two outflows. One of these outflows is the good product (hopefully 99.9% or better) and the other outflow is for defective products. Depending on the product and its defect, the defective product may still be sold. If it is a food product and is only underweight, it can be eaten, possibly showing up in a factory seconds store. Obviously, products with metal filings are recycled, burned for heat value, or thrown away.
The inspection process in one of these machines (or within another machine) can include:
Checking one or more dimensions with mechanical gauging or electrical sensor.
Checking one or more dimensions or features using a vision system.
Checking weight for correct amount.
Checking a liquid’s volume by weight or level.
Checking a filled Stand up Pouch (SUP) for leaks.
Checking a product for metal filings, etc.
Checking a cereal box for the free prize inside.
The results from all of these can range from health risks (metal filings) to disappointed customers (leaky SUPs).
Test Machines
Machines that conduct some performance check on the filled, assembled, or processed product are sometimes referred to as Test Machines. Although some might argue that testing is part of inspection, the distinguishing feature is often the cycling of the product in some or all of its designed operation. In other words, an Inspection Machine functions by either a noncontact mode, or with a simple contact where some measurement or property is determined. A Test Machine makes the product do some action or work, such as cycling a spray head from a hand-powered misting bottle. The test is carried out on either a random basis, or on every spray head if trouble has been observed in the past, but the spray head is either passed as working properly, or is rejected.
As opposed to Inspection Machines being potentially integrated into an Assembly Machine, most Test Machines are separate from the assembly process. Test machines are often highly specialized to the product being assembled or processed, and the devices used to perform the test and to judge the results cannot be easily integrated into the other machines. Following the example of testing the spray head, there would need to be devices to move a single spray head into the test station in the correct orientation, an actuator to perform the test, a device to advance spray heads that pass the test, and another device to dump a rejected spray head into a hopper. The controller may need to be smart enough to allow the spray head to be actuated a variable number of times, so as not to reject heads that are good but not the best performers. Remember here, we are talking about something that goes on top of a bottle of kitchen cleaner, not a $250 cell phone. So if a spray head does work with one or two extra pumps, the company’s marketing group may say to keep it, but if it works in fewer pumps, do not waste time and pass it.
Another option, if the process takes significant time and the product throughput rate is significant, is to test a set of products as a group or gang at one time. Perhaps the same pump spray actuator can be used for six spray heads at a time. However, six separate sensors will be needed to judge each spray head’s individual performance, and six different actuators are needed to dump the bad product selectively. No-one can afford to dump all six spray heads if only one is bad.
Packaging Machines
Any finished consumer product of any value gets packaged in one of many different types of packages. It can be bags, boxes, cartons, SUPs, aseptic boxes, and more. None of these packages significantly improves the performance of the product inside, but the packaging does help the consumer understand the product, differentiate the product from the competition, and improve sales dramatically. One packaging user’s group even had the 2001 slogan, “Packaging Matters.” Commonly found Packaging Machines include:
Closing filled corrugated cardboard boxes;
Filling bottles with liquids;
Filling bags with dry products;
Placing products into cartons;
Weighing products for accuracy;
Metal detection for safe consumption by consumer.
As you will note, the last two machines have been discussed in the previous section. Trying to segment the market and production of automation is a gray area. Packaging Machines are such a large and important group that they will be covered in a separate blog post later on.
Interesting read but a lot of it could have been shortened. You mentioned there will be a separate blog post for packaging machines later on. When should I expect to read that?