Here’s a guide to specifying screws and barrels that will last under conditions that will chew up standard equipment. Highly polished FTXC-4000 bimetallic screw, with overall chromium carbide coating, offers advantages over flight-top hardfacings.
Pitting on the surface of this feedscrew made with regular 4140 HT steel is a result of processing highly corrosive polymers. Extreme wear on these screw flights was caused by binding due to a difference in coefficient of thermal expansion between the barrel and screw. Severe scouring of this screw surface was also a result of binding due to a mismatched barrel and screw combination. Corrosive, abrasive, and high-temperature resins can degrade screws and barrels before you know it.
Processors have to closely monitor the effects that their resins are having on the equipment to avoid production inefficiencies and potential part-quality problems.
Screws and barrels should be examined, measured, and pulled for rebuilding or replacement when needed because even minimal wear affects production and threatens quality. The best way to protect equipment against abrasive and corrosive resins is to select screws and barrels constructed of the right materials to protect against wear from the types of plastics to be processed. Corrosive wear such as pitting on the surfaces of barrels and screws occurs when metal is attacked during processing by acids and acidic gases, which can dissolve oxide coatings. Resin manufacturers are generally happy to provide equipment recommendations for processing their products.
DuPont also notes that hardened electroless-nickel plate can be used, but even small holes, chips, or cracks in the plating can degrade performance. NatureWorks, manufacturer of Ingeo bioplastics, recommends use of stainless steel for all processing equipment to minimize corrosion, noting that PLA should not be left in the extruder, polymer filter, transfer lines, or other part of the extrusion system at melt temperatures for extended periods. Corrosion-resistant materials have a lower coefficient of thermal expansion (CTE) than standard steel, which can cause trouble during processing high-temperature resins such as fluoropolymers.
Abrasive wear, which is caused when gritty reinforcements and other hard particles scour the barrel and screw surfaces, can be combated by using hardened, wear-resistant alloys and coatings. Screws often are surfaced with hard cobalt- or nickel-based weldments or manufactured with tool steels that can be case-hardened or through-hardened. When used with corrosion-resistant screws, HIP barrels are said to reduce substantially the absorption of iron particles from the barrel bore into the melted polymer. The screw should be pulled and thoroughly cleaned while still hot to check the flight OD and the barrel ID on a regular basis. Once the barrel is purged of all plastic, an electronic bore gauge is inserted into the barrel, and readings are taken at every inch mark to generate data on the condition of the ID.
Taking those measurements on a regular basis to determine rate of wear will enable the operator to predict when the screw or barrel will need to be replaced or repaired and to schedule the downtime during a favorable time. Once a screw is worn past a certain point, the melt starts coming back over the flights, causing both screw and barrel wear to accelerate further. Psoriatic nail dystrophy mainly occurs in patients who also suffer from psoriasis of the skin. If there is any diagnostic uncertainty samples must be sent for mycology to rule out tinea. Even our immune system makes mistakes and this can lead to an autoimmune disease called psoriasis, which affects the skin. There are five kinds of psoriasis namely guttate, plaque, pustular, inverse, and erythrodermic. Based on studies, researchers found an anomaly in gene mutations, particularly the chromosome 6 or PSORS-1, which eventually affects the T-cells. When a person acquires psoriasis, the only things that he or she can do is to limit the symptoms and prevent further infections. There are topical that can be bought without doctor’s prescriptions but it is still advisable to expert advice. Injectable medicines and pills that address the immune system will be likely recommended but most often, a patient will have to get approval from a physician. Most doctors recommend immune suppressants like cyclosporine or methotrexate for treatment of psoriasis that is already critical.
Phototherapy is another known psoriasis treatment that works by carefully exposing the skin to ultraviolet rays.
There are lots of treatments, most of them involve heavy medication considering that psoriasis can affect the whole body.
Lymphedema can develop in any part of the body, and it typically occurs in the part of the body that is “drained” by lymph nodes for that specific area. The characteristics of Stage 1 include puffy appearance of the hand or foot (farthest point on the limb). In Stage 2 lymphedema, the swelling takes on a spongy consistency and “pitting” is less present.


At this stage, the skin typically becomes very dry and scaly and the limb or other affected body region becomes very large. Offers PicoSure laser tattoo removal, CoolSculpting, fractional CO2 skin resurfacing, Botox, Juvederm + more to improve conditions like acne, winkles, spider veins, spots, unwanted hair. Super-pulsed Fractional CO2 (carbon dioxide) laser – the gold standard in laser resurfacing technology.
The SmartSkin™ CO2 laser uses small columns of fractionated energy to ablate areas of damage.
By targeting zones deep in the skin as opposed to the entire skin surface, SmartSkin™ offers improvement in wrinkles, discoloration, and scarring by stimulating collagen production and skin tightening. SmartSkin™ CO2 resurfacing can erase years from your face and dramatically improve the appearance of wrinkles and pigment, but it is not a lunchtime procedure.
The intensity varies based on the treatment parameters used during your SmartSkin™ procedure. For best possible results, it is important that you carefully follow specific skin-care instructions Mill Creek Skin & Laser provides you. SmartSkin™ delivers micro pulses of energy, your recovery time is significantly shorter than the fully ablative lasers. The best way to avoid any complications is to select a good dermatology office with extensive experience in lasers.
Pain: Most people may feel uncomfortable during treatment due to the measures discussed above.
Wound Healing: The CO2 laser causes a superficial wound to the skin that takes approximately 2 to 10 days to heal. Since every patient is an individual, you may not respond exactly the way other patients do. Treatment is limited by skin color, which can be evaluated at the initial free consultation.
Certain engineering materials, thermoplastic elastomers, plus the wave of newly developed biopolymers, often create a corrosive condition that can quickly degrade equipment. A preventive maintenance (PM) program that includes frequent inspection for corrosive and abrasive wear is required to maintain processing standards.
DuPont makes it very clear that special corrosion-resistant materials must be used for all parts of extrusion equipment that come into contact with the melt when processing its Teflon fluoropolymers.
Tungsten alloys for barrel linings and screw hardfacings offer excellent protection against abrasive wear. For screws, medium-carbon, heat-treated steel is typically used as a base on which hardfacings are welded to the tops of the flights. Colmonoy 56, a nickel-chrome-boron alloy, is often used to protect screws against mildly corrosive and mildly abrasive resins. Among the best in terms of corrosion resistance are HIP (hot isostatic pressing) barrels for injection molding and extrusion. Too much clearance between the screw flights and the surface of the barrel can affect the machine’s performance, efficiency, and energy consumption. A PM program is equally important when part quality is critical, as when producing medical tubing and components for medical devices. Plastic materials on the surface of the screw and barrel can be removed with a wire brush and copper gauze.
A serious wear condition wastes a significant amount of resin and causes a drop-off in productivity. It is important to not only include nail clippings but also scrapings from the undersurface of the nail plate, otherwise many cases of tinea will be missed.
It occurs when the immune system mistakenly identifies skin cells as pathogens or disease carrying organisms. Among the five, the most common is plaque psoriasis, which is characterized by scaly patches of red and white on the epidermis (the outer layer of the skin).
On a normal cycle, the human body sheds skin every 30 days but people with psoriasis experience the changes in one week or a little over. Most of these topical may include shampoos, lotions, and ointments that have cortisone, anthralin, salicylic or lactic acid, vitamin D, and retinol or vitamin A. For example, if you had lymph nodes removed under your arm (axillary lymph nodes), you could develop lymphedema in the chest, back, or arm on that same side.
Protein molecules can accumulate beneath the skin and “pull” extra water into the affected area, occasionally resulting in sensations of heaviness or fatigue in the limb or region. We carry products from Oxygenetix, Colorscience, Latisse, Obagi, Jane Iredale, Clarisonic, SkinMedica, and more. Tiny wounds are made and the surrounding healthy skin helps with healing, making new collagen and elastin. These microscopic holes quickly heal within 3-7 days, after which you will be able to apply makeup on the treated surface and return to your normal lifestyle.


Additional improvements will continue for several months as the collagen rejuvenation process takes full effect. However, the CO2 laser treatment is a nice compliment to Botox, fillers and the Affirm laser. There is discomfort for the first few days after treatment, but Tylenol or Motrin is effective for it. The superficial injury of the outer layers of the skin may result in mild to moderate swelling.
This includes hypertrophic scars or, very rarely, keloid scars (thick, raised scar formations.) It is important to inform us of prior history of unfavorable healing. It is important to keep your eyes closed and have protective eyewear at all times during the laser treatment.
Reinforcements such as glass fibers, spheres, and other fillers and additives are abrasive and also take a toll on equipment, especially feedscrews and barrels. Standard bimetallic, nitrided, or tool-steel barrels can be severely damaged by fluoropolymers in a very short time. The materials of choice are nickel-based alloys such as Hastelloy, Inconel, Monel, and Haynes, which are not affected by the acids. Matching the screw and barrel is important due to the lower thermal conductivity of corrosion-resistant materials.
Even fluoropolymers are no threat to these barrels, which have a protective layer of nickel-rich boron alloy containing molybdenum and a matrix of borides and carbides. Nickel-chrome and tungsten barrels can be used as long as the barrel discharge end is cast in Inconel and the surfaces of the transducer holes and flanges are made with Inconel as well. In extrusion, wear conditions result in lower throughput, requiring an increase in screw speed and energy use. Precision wear measurement instruments, accurate and easy to use, are available in a variety of sizes and capabilities. Repair services can give renewed life to worn components at lower cost than complete replacement. These may appear in various areas of the body including scalp, hands, toes, knees, and elbows. The disease is also recurring, which means that recovering from it does not make a patient psoriasis-free for life.
Despite a “normal” measurement of tissue or limb sizes in that area, the early changes leading to lymphedema have begun and generally respond to treatment. This tissue consistency change is caused by the formation of fibrosis, or scar tissue, with gradual thickening of the tissues on the limb as it increases in size. Treatment of lymphedema focuses on halting this progression while also improving the symptoms.
This is more common in patients who have a history of flushing and blushing easily or who already have dilated vessels on the surface of the skin. Hyperpigmentation usually fades in 3 to 6 months, though rarely pigment changes can be permanent.
To minimize chances of scarring, it is important to follow post-operative instructions carefully. Psoriasis affects approximately 1-3% of the total population on Earth, specifically those at the age of 15 to mid 30s. A little bit of sunlight is also good for the skin as long as the person does not get overexposed. This stage should not be ignored—instead, prompt treatment will reduce the risk of worsening edema. Excess skin projections (including blisters) can form to attempt to contain the fluid, and these projections pose an even greater infection risk.
Extruder barrels typically have to be resleeved along the whole length, which is more expensive and not always cost-effective. If you have chronic swelling, ask your doctor about the options to prevent skin breakdown such as a pressure-reducing mattress, a lamb's wool pad, or a flotation ring. Maintain everyday activities.
This could be due to lower protein content of the lymph fluid early in the development of lymphedema, or the fact that lymphedema hasn’t been present long enough to result in fibrosis. When lying down, keep your arms and legs above the heart level, if possible, to encourage drainage.
Your fluid intake and output should be monitored, and you should be weighed daily. Avoid alcohol if liver disease (such as cirrhosis or hepatitis) is causing the problem.



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