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Two of the most popular industrial processes for creating metal parts are die casting and CNC machining. Both processes can even be combined for the best possible finish. However, when it comes to choosing one process over the other, there are several important factors to consider. Read on to find out when you should use die casting and when you should use CNC machining.
What is the difference between die casting and CNC machining?
Die casting involves melting metal and injecting it into a steel mould (the die). The metal is then cooled down so that it hardens in the shape of the part. CNC machining, or Computer Numerical Control machining, automates the process by using a robot to sculpt the part from the metal. Both of these processes are frequently used to manufacture metal components and fittings for objects that we use every day – such as car and computer parts.
Should you choose die casting or CNC machining?
CNC machining tends to be more expensive than die casting, but this depends on the type of parts and level of production. Often, CNC machining is used to create the die, and/or to add more intricate features after a part has been die cast.
If you want to compare the separate processes for forming a part, here are several of the major deciding factors:
Volume
If you are only producing a low volume of parts, CNC machining has the advantage because it doesn’t require tooling costs. On the other hand, when it comes to high volume production, die casting is the better choice for consistent quality and quantity. Die casting is best for durable mass production, while CNC machining is best for small runs of particularly complex or oddly shaped parts.
Speed
Die casting is much faster than CNC machining and easily repeatable. Even if machining is required post-casting, it will still take far less time than machining a detailed part from a solid block of metal. This speedier production cycle makes die casting more reliable for producing large batches. That said, CNC machining can create a faster lead time when it comes to producing smaller volumes, as long as you have the digital model ready. It can also be faster when testing prototypes.
Precision
Die casting can precisely form complicated geometrical shapes, but can sometimes result in surface defects such as burrs or flashes which require machining to clean up. CNC machining can create finished parts with great precision and tolerance, especially if they are highly customised small parts. However, die casting is still a great choice for creating identical parts when the surface detail can be engraved into the master mould.
Waste
There is very little scrap metal left after die casting, which makes it more affordable. CNC machining can leave a lot more scrap behind when carving away layers of a metal block. If you are concerned about minimising waste, but would prefer to use CNC machining, it is important for a recycling system to be in place in order to reuse the scrap metal.
Maximising your returns
It is sensible to be cautious about initial investment in a project, especially if there is a strict budget. If you are unsure which is the optimal method for you, it is best to discuss this with experts. Lupton & Place are leaders in die casting throughout Europe, and also offer in-house CNC machining.
Tolerances in CNC machining are defined as the acceptable range a parameter can deviate from its intended value. A parameter may be a measurable physical property such as temperature, humidity, noise levels, stress, solar irradiance and speed, or a physical dimension, for example, the definition of space. To avoid unexpected tolerance in CNC, the following article you should read.
It specifies the permissible limits of variation before a value is deemed out of place. In engineering, tolerance can be viewed as the permissible degree of error. Tolerances typically have an upper limit which is the maximum allowable positive deviation, and a lower limit which is the maximum allowable negative deviation.
Tolerances used in CNC machining
The term tolerance is used in two different contexts in regards to CNC machining: in terms of CNC machines and in terms of design for CNC machining.
Tolerance in the context of CNC machines is the degree of dimensional accuracy a machine can achieve when machining a part. CNC machines are highly accurate with some machines being able to produce parts to an accuracy of ± 0.0025mm. That’s the size of a quarter of a human hair. However, the tolerances of different CNC machines vary and are usually specified by the manufacturer, for example, 0.02mm is a typical average tolerance. CNC machining service providers also specify the tolerance of their machines to customers.
In design and manufacturing, tolerance is the acceptable range of variation of the dimensions of a part, that will still allow full functionality of the part. Tolerances are determined by the designer and are based on the function, fit, and form of the part. They are especially crucial for components that mate or interfere with other components. For example, the parts for an electric engine would need to have a higher tolerance compared to a door handle. This is because the former has a lot of features that mate with other components. A tolerance is represented by a numeric call-out written beside the dimension to which it applies.
There are different types of tolerance including limit tolerances, unilateral tolerances, bilateral tolerance, and a system of tolerances known as geometric dimensioning and tolerancing (GD&T).
Limit tolerances
Limit tolerances are two-dimensional values that specify the acceptable range of a dimension. The upper limit specifies the maximum acceptable dimension while the lower limit specifies the minimum acceptable dimension. Any value in between these two is acceptable. 0.55 – 0.65 mm is an example of a limit tolerance, with 0.55 mm as the upper limit and 0.65 as the lower limit.
Limit tolerances for a shaft and a hole in CNC machining
Limit tolerances for a shaft and a hole
Unilateral tolerances
A unilateral tolerance is one in which only one direction of variation from the specified dimension is permitted. The direction may either be positive or negative (addition or subtraction from the specified value). An example of a unilateral tolerance is 1.5 mm +.000/-.005. This means that the dimension may deviate as high as 1.505 mm but cannot go any lower than the original specified value of 1.5mm.
Unilateral tolerances in CNC machining
Unilateral tolerances
Bilateral tolerance
Bilateral tolerances for CNC machining are symmetrical around the base dimension. This means that the upper and lower limits deviate from the base dimension by the same value. As opposed to unilateral tolerances, the deviation in bilateral tolerances occurs in both the positive and negative directions.
Geometric Dimensioning and Tolerancing (GD&T)
GD&T is a superior, more difficult system than standard dimensioning and tolerancing (SD&T) It not only provides the dimension and tolerance of a part but also specifies the exact geometric characteristic of the part the tolerance applies to. While SD&T covers shape, GD&T goes further to also cover geometric characteristics such as flatness, true position, and concentricity.
GD&T System
GD&T System
Tolerances tips for CNC Machining
Tolerancing is the process of adding tolerances to your dimensions when designing a part. The following are important tips to note when tolerancing for CNC machining:
Tolerances are very important to your design. However, not all the features of a part need to be toleranced. In order to save machining time and cost, only apply tolerance to crucial features such as features that mate or interfere with other parts.
Avoid unnecessarily tight tolerances. Tight tolerances often cause increased scrap production, special measurement tools, additional fixturing, and longer cycles. These all lead to increased machining costs.
Usually, when tolerancing you also need to keep in mind the tolerance capability of the CNC machines that will machine your part. But when you order your parts from Xometry, you don’t have to pay attention to this because we have over 5000 CNC machines in our network, which makes it possible to find a suitable machine for your project that would keep the tolerance you need.
Keep peculiarities of the material in mind. The difficulty of machining a part to a particular tolerance is very dependent on the material the part is made from. As a result of the material flexing during machining, soft materials make it harder to hold a specific tolerance.
According to an article published in Forbes, the manufacturing sector of the economy is growing even as unemployment remains above 8%. Technology has been cited as the main reason manufacturing is expanding. This is because most industries now rely on CNC machining, and people who can operate such machines are almost assured of a paycheck.
However, the ongoing COVID-19 pandemic is threatening to slow the progress, and it’s more important than ever to know how to reduce the costs of manufacturing parts using this technology.
“Time Studies are always key to knowing what the cost will be on a job, along with tooling usage. If a company can focus on those two items along with material costs, that is the best bet to understanding how to save money on a project,” explains Tom Kohm, President & CEO of Premier Equipment, a leading seller of used CNC machines.
Here are a few other ways to avoid spiraling costs.
Check Your Material Usage
Everyone wants to use the best materials in the market to manufacture parts. However, if there is an option to use something less costly, it can help you to save on the overall production costs. For instance, prototypes are simple parts that are used for smaller functions. Because of that, there is no point splashing a lot of money on creating them when you can access more affordable options. However, when working on parts that call for high-quality materials, you have to find them because they ensure that you come up with effective parts that prevent you from spending more money in the future.
You Can Reduce CNC Times by Optimizing Setups
Every downtime translates into the loss of money because your machines will stop working when you should be churning out new parts. If you have to stop the machines to change the setup, you should know that you will end up being less productive. To avoid this, you need to optimize the process so that some parts load automatically. The machine can be kept running when the number of setups is minimized.
Loosen the Tolerance to Lower Costs
The expenses will skyrocket if you always need more precision to finish a component. You will also find it difficult to avoid wastage when tighter precisions are not met. Because of that, you may want to loosen the tolerance and notice the difference. In addition to that, a lot of time is saved when you use standard tolerances. Be sure to check the machine’s specifications to understand what standard to use. Also, if you are milling multiple holes, you should consider using identical dimensions as this will save a lot of time.
Kohm adds one additional suggestion, “Of course, purchasing a used CNC machine over a new one gives an instant cost savings, if a shop needs to acquire the machinery needed to complete the application.”
We have all heard of the many things in our lives that can be bad and harm us and I believe that knowledge is the key to good health. Let’s face it; companies are out to make money, as much as they can, so often we don’t hear the whole truth. Here are some facts about aluminum foil you may have not heard about.
Aluminum foil is a neurotoxin
Oxford’s dictionary defines neurotoxin as; neu·ro·tox·in (noun)
· 1.a poison that acts on the nervous system.
Aluminum is a naturally occurring metal in the earth. We are all exposed to small amounts of it from the air, food, water, and soil. According to the World Health Organization (WHO), the acceptable dose of aluminum per day should not exceed 1 mg per kg of body weight.2 Many sources show that on average we consume about 9 mg aluminum per day in food.4
Researchers say that, because aluminum has no physiological role in the human body, it has the potential to cause significant detrimental effects when consumed.
Scientists are finding out that increased levels of aluminum can negatively affect brain function. They have said that over-exposure to aluminum can cause memory impairment, learning difficulties, central nervous system disorders, Parkinson’s disease, and Alzheimer’s disease. Sounds like a neurotoxin to me!
The finding from International Journal of Alzheimer’s Disease after looking at the aluminum-Alzheimer link found that people with Alzheimer’s disease have elevated levels of aluminum in brain cells. This journal reports that aluminum can enter the bloodstream through the gastrointestinal tract and then that same aluminum can enter the brain through the blood. This can cause severe health problems in people, especially infants, the elderly, and people with kidney disease.5
The journal Neurotoxicology also published a study and found that exposure to aluminum does affect brain function and causes “behavioral, neuropathological, and neurochemical changes.” They recommend that “avoidance of aluminum exposure, when practical, seems prudent.”6
This theory was also proven when a 2014 study showed that a 66-year-old man who died with Alzheimer’s disease had significantly elevated aluminum content in his brain, following eight years of occupational exposure. While the study noted that it was the respiratory system that was exposed to aluminum dust, we now know that there is a direct link between aluminum ingestion and Alzheimer’s disease.
The author of the (2102)study and Head of the Chemistry Division at Ain Shams University, Ghada Bassioni states, cooking with aluminum foil can cause levels of aluminum in food that are unacceptable according to the values outlined by the WHO.2
The Agency for Toxic Substances and Disease Registry says that aluminum toxicity can affect health. They have linked exposure to aluminum to decreased functions of the central nervous system, Alzheimer’s disease, and bone diseases.4
Aluminum foil is not fully inert meaning it can react. Food cooked or prepared in aluminum foil has been shown to have significantly higher levels of aluminum than if they were prepared in another way.
Aluminum is a truly remarkable metal. Due to its signature properties (malleability, rust and corrosion resistance, etc.) countless individuals have taken aluminum and have used it for numerous applications. If you are like many, it can be difficult to understand what exactly the uses of aluminum coil are. Do not worry. Wrisco has prepared a small list of industries and practices that rely on aluminum coil to get the job done. So if you are curious to know what the uses of aluminum coil are, then continue reading below.
THE USES OF ALUMINUM COIL
TRANSPORTATION
You might be surprised to find out that the construction of most forms of transportation is actually made with aluminum coil. Transportation vehicles such as automobiles and cars are manufactured from aluminum coils. This is because such vehicles will require components that are lightweight, durable and not rust easily since they will be used daily. Parts of most transportation vehicles that rely on aluminum coil for construction include engine components, air conditioners, radiators, wheel hubs, car doors and much more.
ARCHITECTURAL DECORATION
Thanks to its corrosion resistance, strength, and incredible processing and welding performance, aluminum coil will be often utilized a lot for architectural decoration. Other than surface decoration, most building projects rely on aluminum coil to help design structures, doors, windows, ceilings, curtain wall profiles, pressure plates, color coating sheets, etc.
ELECTRONIC APPLIANCES
Although this metal is not as electrically conductive as copper, aluminum coils are often utilized within many electronics. Aluminum is often particularly used in wiring as their corrosion resistance guarantees that wires will last for a long time. This is why objects such as power lines and air conditioners with electrical components are able to withstand the elements for a long time. This is why most electronics, in general, have a fairly long lifespan.
FOOD INDUSTRY
The main reason why food cans are made with aluminum coils is because of aluminum’s malleability, rust and corrosion resistance. Thanks to its malleability, aluminum cans are able to be easily manufactured in mass quantities. Due to its rust and corrosion resistance, aluminum is able to guarantee that the food within the can will be able to stay fresh for a long time. Besides cans, aluminum coils aid in the production of lid caps, bottles and other packaging.
AND MUCH MORE
Aluminum is such a versatile metal. Because of this, aluminum coils are utilized for a wide variety of reasons. Though we have listed some applications above, there are many more industries and practices that aluminum coils are used for. If you find that you need a metal type to help assist you in the production or function of a certain object or item, you very likely might just benefit from purchasing aluminum coil.
Choosing between these two types of hollow section aluminum extrusion comes down to the application. Structural tubes are preferred in some and seamless work better in others. Here’s a summary of the strengths and weaknesses of each.
Structural Aluminum Tubing Pros:
Very consistent wall thickness around the cross-sections
Can be extruded faster than seamless (which brings down the price)
When extruding small cross-sections it’s sometimes possible to fit multiple opening in a single die, increasing efficiency and lowering the cost per foot
Structural Aluminum Tubing Cons:
Welded seams create a region of weakness where the tube could rupture if subjected to high internal pressure or significant bending
Seams may be visible on the surface and will be highlighted by anodizing
The seam is where corrosion is most likely to start, (although most grades of aluminum don’t corrode to any significant extent.)
Seamless Aluminum Tubing Pros:
Higher-strength/resistance to deformation and internal pressure
Uniform appearance when anodized
Seamless Aluminum Tubing Cons:
Slower extrusion process (which can increase the price)
Inferior concentricity of internal to the outer diameter
We can summarize the arguments this way: If the application involves internal pressure or the extrusion will be subjected to significant deformation, choose seamless. If neither of those apply, ask how concerned you are about appearance. If the answer is, a lot, seamless is probably the correct route. However, if the highest priority is keeping the cost down, pick structural.
Applications for Seamless and Structural Aluminum Extrusion
Seamless extruded tubes are used in applications that involve internal pressure. Hydraulic cylinders, pipes, and fittings are good examples. They are also used when the extrusion will be put through significant deformation. A good example of this bending electrical conduit or bus bars.
Another group of applications are those involving high loads that will deform the tubing or extrusion if it isn’t strong enough. Examples of this type include aircraft seat frames, baseball bats, and driveshafts.
You might also choose seamless when appearance is important. This is especially true if the extrusion will be anodized as that tends to highlight the seam.
Structural tubing is appropriate for all those applications that don’t apply high forces. Railings and window frames are examples, along with wall framing and other architectural and decorative uses. Frames for enclosures, material handling carts, and machine guards are more industrial examples. Many applications in trailers and RVs are well-served by structural tubing too.
An Important Decision
As structural tubing is less expensive it tends to be the default choice. Before specifying structural tubing though, remember to consider the application. It will work most of the time, but in some situations, it could be an expensive mistake. If you’re unsure which direction to go in, we’ll be happy to discuss your application with you.
Chal seamless tubes are produced using two methods. One method pushes a hollow aluminum billet through a Die and Mandrel Press with tremendous force at high temperatures. The other method pushes a solid billet through a Piercer Press and then a mandrel pierces and extrudes the billet in a second forward stroke. Regardless of the method used, the tube will have no weld or seam, making it ideal for anodizing and other finishing procedures.
Advantages of seamless tube and pipe:
No weld seams, preferred for pressure vessels
More uniform anodizing appearance, especially on heavier wall sections
No weld seams that could split in forming operation
Increased structural integrity
Structural Tube:
Hydro structural tube is produced with either the porthole or bridge die method. Solid aluminum billet is pushed through the die with tremendous force at high temperatures. The tube separates during the process and is formed back together by an inherent welding process while passing through the extrusion die. There is a slightly visible seam that may be noticeable to the naked eye if the tube is anodized or "finished."
Advantages of structural tube and pipe:
Improved control of wall thickness eccentricity
More ability to use multi-hole dies for smaller diameter sizes to improve productivity, decreases costs
Seamless Tubing Applications
Seamless pipe and tube is typically used for pressure vessels, hydraulic cylinders, compressed gas cylinders, drive shafts, lighting applications and bus conductors. They are recommended for applications requiring:
Critical pressure ratings
Demanding forming applications
Critical strength requirement
Uniform anodizing appearance
Aluminum Tubing Options
As a widely used aluminum profile shape, aluminum tubes are available in square, rectangular and round shapes in a range of sizes based on the outside dimensions. The tube’s strength is a factor of the aluminum alloy used, the thickness of the walls, and the size of the tube. Round tubes are available in the widest variety of sizes, from an outer diameter of 5/8 inch to 16 inches and wall thicknesses of 1/16 inch to 1 inch.
Lubricating oil in its passage through a diesel engine will become contaminated by wear particles, combustion products and water. The centrifuge, arranged as a purifier, is used to continuously remove these impurities. How to select a perfect Lubricating Oil Purifier for you? let’s see.
The large quantity of oil flowing through a system means that full flow lubrication would be too costly. A bypass system, drawing dirty oil from low down in the oil sump remote from the pump suction and returning clean oil close to the pump suction, is therefore used. Since this is a bypass system the aim should be to give the lowest degree of impurity for the complete system, which may mean running the centrifuge somewhat below the maximum throughput.
Water-washing during centrifuging can be adopted if the oil manufacturer or supplier is in agreement; but some oils contain water-soluble additives, which would of course be lost if water-washed. The advantages of water-washing include the dissolving and removal of acids, improved separation by wetting solid impuritiesj and the constant renewal of the bowl liquid seal. The washing water is usually heated to a slightly higher temperature than the oil.
Detergent-type oils are used for cleaning as well as lubricating and find a particular application in trunk-type engines and some slow-speed engines. Detergent-type oil additives are usually soluble and must not therefore be water-washed.
Steam turbines
The lubricating oil purifier in a steam turbine will become contaminated by system impurities and water from condensed steam, so bypass separation is used to clean the oil. The dirty oil is drawn from the bottom of the sump and clean oil returned near the pump suction. Preheating of the oil before centrifuging assists the separation process. Water washing of the oil can be done where the manufacturer or supplier of the oil permits it.
Related Information:
Lubrication Schedule and Orders
The lubrication system of an engine provides a supply of lubricating oil to the various moving parts in the engine. Its main function is to enable the formation of a film of oil between the moving parts, which reduces friction and wear. The lubricating oil is also used as a cleaner and in some engines as a coolant.....
Function of Lubricating oil filters
Lubricating oil filters can be found both on the suction and discharge sides of the lubricating oil pump dependent on the installation and type of engine or engines. Their maintenance is absolutely critical to the life expectancy of the crankshaft and its bearings, which depends entirely on an uninterrupted supply of clean and correctly filtered oil.....
Lubricating oil treatment
lubricating oils require treatment before passing to the engine. This will involve storage and heating to allow separation of water present, coarse and fine filtering to remove solid particles and also centrifuging......
Lubricating oil centrifuging
Lubricating oil in its passage through a diesel engine will become contaminated by wear particles, combustion products and water. The centrifuge, arranged as a purifier, is used to continuously remove these impurities....
Cylinder lubrication & maintaining sump level
The sump level is to be according to manufacturers/shipbuilders instructions . The ‘Sump Quantity’ is always maintained at the same safe operating level and is given in litres. It is essential that the figures are mathematically steady and correct from month-to-month, taking into account consumption, losses and refills and reported .....
Transformer oil is a mineral based oil that is commonly used in transformers for its chemical properties and dielectric strength. This oil in your transformer acts as an insulator and a cooling agent. Over time, the oil will degrade resulting in the potential for faults and costly repairs. With a proper preventative maintenance program, you can avoid any costly down time and expensive repairs.
The quality of your transformer oil will effect its insulation and cooling properties. Under normal operating conditions, a minimal breakdown of oil quality will occur from oxidization and contamination. These are summarized as follows:
Oxidization is acid that forms in the oil when it comes in contact with oxygen. The acid will form sludge which settles on the windings of the transformer resulting in reduced heat dissipation. The windings will run hotter thereby creating more sludge which in turn will create even more heat. The high acid content and increased temperatures will accelerate the deterioration of the insulating qualities of the oil and if left untreated will cause the transformer to fail.
Contamination commonly found in transformer oil includes water and particulate. The presence of either of these contaminants will reduce the insulating qualities of your transformer oil.
Testing
Testing your transformer oil should be part of your yearly preventative maintenance program. Testing the oil will help to determine when corrective measures are required. Initial testing will establish a base line for comparison and annual testing will plot any changes internally in your transformer.
The following 5 part test is a minimum requirement of an annual maintenance program:
Dielectric breakdown: Dielectric strength is a measure of voltage the oil will insulate against. Many contaminants conduct electricity better than oil therefore lowering the dielectric breakdown.
Neutralization/Acid Number: This test will measure the level of sludge causing acid present in the oil.
Interfacial tension: This test identifies the presence of polar compounds. These would indicate oxidation contaminates or deterioration from the transformer materials. i.e. paint, varnish, paper.
Colour: The colour of the oil indicates quality, aging and the presence of contaminants.
Water content: This tests for the amount of water present in the oil in parts per million. The presence of water in your oil will decrease the dielectric strength.
The Dissolved Gas Analysis (DGA) test is another useful tool as part of your maintenance program. Examining the gasses present in the oil can help determine if there are faults in the transformer including arcing, corona or overheated connections.
The results of the tests performed will help determine when further action is required. Predetermined limits for these tests must be set based on the voltage class and KVA of your transformer. Any tests performed showing results outside of the predetermined parameters indicate further investigation is required. A downward trend of your test results over time also warrants further testing and an evaluation of the results.
If remedial action is required for your transformer oil, a recent PCB analysis is required in addition to the preceding testing. If the result of the PCB testing is less than 2 ppm, in most cases an onsite reclamation of your oil can be performed. If the oil is over 2 ppm but less than 50 ppm, the oil can be shipped to a recycling facility and your transformer can be retrofilled with new or recycled oil. Any PCB analysis with results over 50 ppm will require special handling.
Remediation Treatment
If the quality of your oil has declined below acceptable levels a decision has to be made to replace or reclaim the existing oil. Often, the rapid degradation of the oil in your transformer indicates that remedial treatment is required for your transformer itself as well as the oil.
Reclamation of your existing oil can be performed onsite with limited down time. It is possible to restore your oil to new oil specifications with a combination of treatments including fuller’s earth and degasification. If some contaminant levels are significantly high, it may be more economically practical to replace the oil rather than reclaim it.
A proactive approach should be taken if your transformer oil has a high acid content. Any sludge formed by the acid has to be rinsed out of the transformer with hot oil to remove the sediment. There is a cost saving to you if the oil is reclaimed in the early stages of the acid build up, before the sludging occurs, as the oil will retain its quality longer under normal operating conditions.
Reclamation of oil with a high acid content includes fuller’s earth treatment to remove acid and particulate, and degasification to remove gasses and water. This process will also correct the acid number and the colour.
Transformer oil can hold water particles in suspension depending on the temperature of the oil. If the oil is at its saturation point, there is likely to be free water at the bottom of the transformer. The dielectric strength of the oil is decreased with water present in the oil and a degasification of the oil is recommended. If the water content is particularly high, a hot oil dry out should be considered. Although more costly than a degasification, this will also remove any water that may be in the core and coil assembly.
If you have decided to replace the oil in the transformer, either new or recycled oil can be used. If the transformer tank is capable of vacuum, it should be filled under vacuum based on manufacturer’s recommendations. If the tank cannot withstand a vacuum, the oil should be degasified into the transformer and circulated through the degasifier three times the volume of the transformer. This will help remove any moisture present in the insulation of the transformer.
New oil often requires further degasification to remove air and moisture added during the transportation and handling process. This will increase the life expectancy of the oil in the transformer.
Environmental Concerns
Mineral insulating oil is a valuable resource that can be recycled many times and returned to its original condition. Using new quality recycled oil or reclaiming your existing oil saves the depletion of a non-renewable resource and can be much more cost effective than replacing with new oil.
A preventative maintenance program for your transformer has both economic and environmental benefits. A failure of a transformer can result in significant environmental clean up costs and considerable replacement or repair costs.
The deep fryer is an absolute staple in the commercial kitchen today. Just think a minute about all of the different fried foods we enjoy: fried chicken, fish and chips, fried shrimp, wings, french fries, onion rings, calamari, and donuts. And that’s just to name a few! No matter where you are, you will likely find most of these fried foods and more at a restaurant near you. As a restaurant owner or operator, you most likely have a least one deep fryer in your kitchen, if not several. If you do have deep fryers in your establishment, are you getting the most out of your fried food program? Are your fryers turning out the best possible quality product? Are you getting the best return on your investment in your fryers?
If you are not filtering your oil, both your food quality and your profit margins are suffering. In fact, oil filtration is one of the most important things you can do preserve the quality of your fried foods and increase your profitability.
Oil Filtration for Food Quality
How can oil filtration preserve the quality of your food? To answer that question, we need to understand how fryer oil degrades over time during use. The four main causes of oil degradation are water, air, sediment, and heat.
First, water usually finds its way into fryer oil in the form of ice crystals from frozen foods. Some water will also render from food as it cooks, especially if it has excessive marinades. Because the boiling point of water is much lower than oil, water is very disruptive to fryer oil. Second, air degrades oil through oxidation as the oil sits out uncovered. Third, sediment left behind from food particles burn, causing off flavors, odors, and darkening of the oil. Finally, the heat itself from the fryer degrades the oil quality over time. As the fryer continues to heat the oil, the smoke point of the oil gradually lowers, causing the oil to smoke and deteriorate.
Remember that oil is food too! You can start with the best quality product, but the quality of your food is only as good as the quality of your oil. Burnt, degraded oil imparts bad flavors and aromas into fried foods. It is also less efficient than clean oil. When you fry with oil that is past its prime, the breading or the crust on the food does not crisp as quickly, and the food absorbs more of the oil. Rather than a crispy, golden brown product, you end up with a darkened, greasy mess. The simple equation here is cleaner oil equals better food, which is why you want to filter your oil regularly.
Oil Filtration for Cost Savings
Depending on how much you use your fryers, fryer oil can easily make up a significant portion of your food cost. As an example, let us consider a commercial kitchen that does not filter their oil and has to replace it twice a week. For one fifty-pound fryer, at an oil cost of $1.00 per pound, that equates to $100 a week to operate that fryer. Over the course of a year, that comes out to $5,200 a year and that is just one fryer! The good news is that studies from major commercial fryer manufacturers have proven that the practice of regular, consistent oil filtration reduces the operating cost of a deep fryer by 35% or more. For a restaurant that operates four fifty-pound fryers, using the same numbers, a 35% reduction in operating cost comes out to an annual savings of $7,280!
Restaurants that filter their oil realize these kinds of cost savings because oil filtration extends the life of your oil. With regular to heavy use, your oil might last three days at best without filtration. With filtration, you can easily stretch that to an average of six or seven days. As we are well aware in the restaurant industry, managing your food cost is essential for profitability. If you operate fryers in your restaurant, and you are not filtering your oil, you are literally throwing money