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Witzel Advantages

2014 Witzel Control Panel3.5" Touch Panel Display featuring:
  • Direct temperature input (no more holding a button to scroll to the temperature)
  • Timer function
  • Graph of the heating process displayed
  • Software update via USB

The Witzel Infrared Oven features an exclusive "smart controller" for controlling surface temperature of the material being heated rather than the ambient temperature of the oven itself.

Download Infrared Oven Guide

  • Never burn plastics again
  • 4 temperature presets
  • Precise infrared heat control

Witzel FAQ - Frequently asked questions

Q1: What kinds of materials can be heated with Witzel Infrared Ovens?

A1: Generally all thermoplastic materials available in the O&P market can be processed. During development we took special care to employ an optical sensor that works equally well with clear plastics as with colored ones. Due to the specific nature of Infrared rays —which enter the material rather than reflecting off —the materials which are heated in an Infrared oven mold better than the ones heated traditionally. Additionally, colors applied through the use of thermotransfer papers are clearer and brighter.

Q2: Do I need Witzel's own blister forming tray to process prosthetic sockets with my Witzel Infrared oven?

A2: No. You can continue using your existing blister forming trays without any limitation. However, it is important to observe the correct distance between material and Infrared tubes. All Witzel Infrared ovens have a metal guide ridge around the inside of the housing which indicates the correct focal length for the tubes. These guides are positioned to work perfectly with Witzel's blister forming trays. To use your existing trays it will be necessary to check the height and, if necessary, adjust the height of your tray to align with the guides in the oven to achieve even heating.

Q3: Is it advisable, necessary, or beneficial to preheat my Witzel Infrared oven?

A3: No. Infrared heat doesn't heat air—only solid objects. "But, wait!?" you say. "After I use the oven I can feel warm air when I put my arm inside." Yes, this is true. But, it is indirectly heated air reflected by the hot sidewalls of the oven, the hot tray and/or the heated material itself. In fact, the thermostat in the oven does not even measure the air temperature. Witzel Infrared ovens measure the surface temperature of the material being heated. And, it is this actual material temperature that is displayed on the control panel. Preheating the empty oven may provide marginally quicker material heating times. But, the resulting heated product will not be superior. We can only state empirically that preheating the oven will waste energy and shorten the lifetime of the Infrared tubes. Witzel advises NOT preheating its Infrared ovens.

Q4: Is there a blower fan available for Witzel Infrared Ovens?

A4: No. As mentioned in Answer 3 above, Infrared heat does not affect air. It only heats solid objects. As such, the air inside the oven is always cooler than the material being heated. Therefore a blower fan in an Infrared oven—while effectively circulating the cooler air's heat more evenly— is actually acting as a cooling fan that has a more negative than positive effect on the heating process.

Q5: My materials tend to shrink a lot when heating up. What can I do to prevent this?

A5: Generally every plastic has some shrinking caused by its “memory” quality. Depending on the manufacturing method this unwanted quality is more or less distinctive. In the O&P field there are several materials available which are marketed as “non shrinking”. Unfortunately, there are other budget-friendly PP or PE materials available which are not sufficient for typical O&P processes due to the high shrinking quality. These low-end materials cannot be used in any open process—either convection or IR oven heat. These products are only suitable for closed systems such as heating presses with rigid plates that are able to provide the needed pressure to hold the material in place. Our recommendation is to source plastics marketed for O&P as "non shrinking".

Q6: Why is my material heating unevenly?

A6a: The most common fault when using Infrared ovens is incorrect distance between material and Infrared-tubes. As mentioned above, Infrared-heat is radiant-heat. This type of heat must be focused for consistent results. During development we took special care to ensure even heating across the entire tray of each of our Infrared ovens. The specific distances between tubes, and varying capacities of heating elements has been designed in to each oven to ensure optimal functionality. To get best results it is absolutely critical that materials be placed at the correct distance from the Infrared-tubes. To assist with this critical requirement, each Witzel oven is fitted with guide rails around the inside perimeter of the oven. When using an oven with a roll-about tray—the IR1302, for example—flat materials should be placed directly on the teflon fabric. Then, once the tray is in the oven, it should be adjusted so that the tray lifts all the way to the top of the oven, hitting the guide rails in the oven. Similarly, when using a blister forming tray to hold a piece of plastic, it is necessary to lower the tray so that the plastic in the frame is even with the guide rail.

A6b: Another cause for uneven heating may be different materials in the oven at the same time. There is a single, optical temperature sensor in the oven. Witzel Infrared ovens are designed to provide an optimal heating algorithm based on the material this sensor reads. If there are thicker, thinner; different colored; or products of a different chemical makeup on the tray simultaneously, you may experience uneven heating. Witzel advises heating only a single thickness, extrusion, and color of a given material at any one time.

Q7: What is the difference between “Gloss” and “Porous” Teflon coatings?

A7: "Gloss" Teflon is smooth, and has a high sheen to it appearing more like a sheet of plastic or thick paper. Beginning in 2012, Witzel Infrared ovens have been equipped with replaceable "Pourous" Teflon coatings as standard equipment. Porous in this context means that the Teflon coating is air permeable, and more resembles a fabric than a sheet of plastic. The advantage of porous Teflon in this application is that air trapped beneath flat plastics during the heating process is provided with a route of escape. This mitigates unwanted voids on the underside of the heated material. Another benefit of the porous Teflon compared with gloss Teflon is that Porous Teflon provides less adhesion when lifting the heated material. This is especially noticeable with soft materials may stretch undesirably when being removed from the tray.

Q8: When heating 2 mm PP sheets, the edges roll up. What can I do to prevent this?

A8: Interestingly this phenomenon does not show up with every 2 mm PP. It may depend of the manufacturer of the plastic. If the plastic was taken from a roll, the direction the material was rolled may also play a part. Should this problem arise you can easily prevent it by putting a sheet of porous Teflon on top of the 2 mm PP when placing it on the oven tray (The Teflon should be a little larger than the material). The Infrared heat will pass through the Teflon without any issue. The extra weight of the Teflon sheet will be sufficient to hold down the edges. You may find it necessary to raise the temperature by one or two degrees Fahrenheit and extend the heating time briefly, as the Teflon may affect the optical temperature readings slightly.

Q9: We have had our Witzel Infrared oven for some time and it always worked as designed. Recently, we noticed our material is starting to overheat or even burn. Using previously working temperature settings we are seeing materials burn that used to heat just fine.

A9:Witzel Infrared ovens are all equipped with an optical temperature sensor which measures the surface temperature of the material. This sensor is located inside the oven, in the top center between the tubes. (To assist in locating the sensor, note that there is a black target on the tray which is directly below the sensor when the tray is positioned for use.) Dust and other pollutants can discolor the glass cover below the optic which can deliver inaccurate readings to the computer. This may lead to either overheating or underheating. This glass cover should be cleaned according to the instruction manual (wipe with a soft cloth, dampened with water only). Witzel advises monitoring the condition of the glass sensor cover and cleaning per the instructions at least every 3 months. Depending on oven usage frequency, this time could be even more frequent. If materials are ever accidentally burned in the oven, either due to a dirty sensor cover, or accidentally setting the temperature too high, immediate cleaning of the glass sensor cover is advised.

Q10: We have 3 phase power in our building. Don't I need a 3 phase oven?

A10:Witzel manufactures 3 phase ovens for Europe. But, we only import single phase ovens for use in the U.S. The reason is that if your building has common 3 phase power service, it is trivial for your electrician to install a two-pole breaker of the required amperage (see the breaker requirements under 'power' in the product description). Because there are no motors being driven, but simply providing current to the heating elements, there is no loss of efficiency in using this method. Atlas has over 15 years experience in delivering these ovens for U.S. power. If you have further questions, please call us at (800) 545-6287.

Q11: The oven says it requires a 30 amp breaker. Can I install a 70 amp breaker and run two ovens?

A11:Without getting in to the NEC code book, a good rule of thumb is: If it has a motor, or heats or cools, the equipment will require its own dedicated circuit. Another NEC code rule states that if the manufacturer requires a dedicated circuit, then code requires it. So, since Witzel states that it requires a dedicated circuit for each of its ovens, NEC code mandates it as well. NFPA 70 110.3(B)