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Pressing 3D Laminates and Blow outs
There are many different tips and tricks to pressing. Often I am asked for formulas however I often find that each company may require different settings based upon the material they are pressing, the profiles, glue type, stage height and so on. One common issue that all companies have or will eventually face are blow outs. During the press cycle you can hear a blow out occur by a pop and a hissing sound. After retrieving the tray from the press you will typically find that dreaded hole and all the parts did not form properly because the press lost its seal. Blow outs are typically caused by either too high of a heat versus too low heat. You can tell them apart because blowouts by too low heat are more like tears and blow outs by too much heat are typically circles or tear shaped holes that seem uniform. Keep in mind that raising or lowering the temperature alone may not solve a cold or hot spot issue. Imagine if you raise the temp but get heat issues but lower the temp and get lack of forming.... Other issues may be at play such as having too short of a preheat. If your preheat is too short then it may be possible that the heat did not have time to soak or penetrate the entire thickness of the 3D Laminate. There are different scenarios where cold spots can form such as using thicker films in a 16 mil to 20 mil where the heat has not soaked all the way through the thickness of the product. Imagine if you are using a very dark color like a Wenge which is almost black and it conducts or absorbs the heat more rapidly however you get cold spots blow outs. Then when you raise the heat you get hot blow outs. The solution to this type of problem can be to do a longer preheat but keeping the temp low enough so that you do not over heat any one particular area of the material. You may also want to use heat strips to ensure you are getting heat distributed uniformly in the press. With membranes on a Shaw Almex, Wemhoner or Italpress for example you may experience less blowouts because the membrane is the source of pressure and that pressure keeps the blowout from occuring. With an Italpresse with no membrane (for example) that inflates the vinyl to the upper platen you get a balloon where the center of the material is touching the platen and heating up very rapidly however the outer portions may not be heating as rapidly and you can actually experience cold spot blow outs towards the outer perimeter of the press. There are two solutions for this type of problem. The first is to have a longer preheat but at a lower temperature so that you get all the material uniformly pliable but not one portion of the film is so hot that it is weakened. There are some machines in which you can reduce the inflation time and then preheat part of the time with it inflated and then preheat part of the time while its not infated. You may need to contact your machine supplier to ensure that your particular model has this option. Another scenario with blow outs can be caused by utilizing the Eco Jig pin system manufactured by Dackor. This pin system is an affordable alternative to automatic systems (although not as efficient as an auto system). In the Eco Jig system you must ensure that the pins are pushed under far enough so as not to create a penetration point for the vinyl to hit. By pushing the pins under further it creates an even distribution of pressing at the bottoms of the doors and will stop blowing out under this situation. In summary, there are many variables which can cause blowouts based upon settings. Step 1: Determine if are having cold or hot blow outs Step 2: If raising or lowering temp does not help then try working with your preheat Step 3: If the above does not work email your settings, machine details and problems you are having to presshelp@dackor.com I hope that this article was helpful, be sure to contact us for further assistance.
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Whitening on the corners of 3D Laminate thermofoil doors
There are many different tips and tricks to pressing. Often I am asked for formulas however I often find that each company may require different settings based upon the material they are pressing, the profiles, glue type, stage height and so on. One common issue that all companies have or will eventually face are whitening on the corners. There are many misconceptions about what causes whitening on the corners and typically the laminate is blamed for the issue. Although the laminate can be a reason it is not necessarily the culprit. Read more to delve into the issues and the solutions on whitened corners on the doors. First I'd like to separate lightening from whitening. I define lightened corners as separations between the print layer and the base film layer and whitened corners as separations between the top cap and the print layer. When you see a corner that is lightened it is typically revealing the base layer of the foil. One over generalization is that a lighter backer of the foil is the issue. When thermofoils are produced typically the lighter backer is used as the base tone of the design. Quality manufacturers have dozens of backers whereas a low end manufacturer may have only a few bases to choose or may use a white backer on a dark woodgrain for example. But most common you will find mustard , almond or chocolate backers on most woodgrains and if any foil is over formed it will reveal the base layer and therefore have whitened or lightened corners. Another common mistake is that you can bend a sample and when it whitens that is evidence that the material will whiten when pressing. When you bend a thermofoil sample and it whitens it typically is forcing the top layer away from the base layer and this is very common among quality manufacturers and will not necessarily cause whitening on the edges when pressing. It in fact shows how they produce their film in respect to the printing layers whether direct printed, reverse printed or at what temperature the material was laminated at. In fact, many high end manufacturers darker colors will whiten when you bend them. So if a sales person grins and bends his sample to show that it doesn't whiten they are trying to show their product is of a higher quality but it is really just a bi-product of how they produce their product or may even show that their company doesn't even have the capability to produce by direct print with a finished top cap. They may actually be showing a weakness of their product and not even knowing it. By bending a sample it will not necessarily stop whitening on the corners when membrane pressing. In the application of miter folding PVC bending the sample does in fact have a direct correlation to whitening issues because the part will be bent at a lower temp whereas in membrane pressing the part is formed at full temp. Want to know how to tell the difference between a top cap separation and a print layer separation?.... The key way to tell is if your parts lighten to a clear or bluish edge or if they whitened to the color of the base of the film. If they whiten to the base of the film then its not caused by the top layer separating. If the corner of the door is in fact bluish or clear in tone you can test it by rubbing it with a block of wood or flaring it with a heat gun. In a miter folding application of a thermofoil a wooden block or heat gun can be used to reseal the top cap to the whitened area. In a membrane pressing application the key will typically be to use a higher heat so that it soaks through the foil and does not cause a separation between a top cap and a print layer. The most common problem with lightened corners are caused by either too much or too little heat. With too much heat you will over stretch the material and will typically find the outer doors that do not have jigs or are not on the edge of the table. The material is heated up too high and then there is no jig or tray filler to capture material and then the laminate may get over stretched on the corners. A simple solution is to put a jig / tray filler close to the edge. Another common problem with lightened corners are caused by too little heat. When the material is too soft or has cold spots on the table the material can separate on the print in the areas where it is being stretched the most which is typically the edge or corners of the doors. You can put a heat strip in various places on the press to find any cold or hot spots in your table. For darker colors such as a Wenge which has ticking you may also find that these darker colors are more likely to have too much heat applied to fast. What I mean is that the dark woodgrains are likely to absorb heat faster than a lighter woodgrain and especially when using bulb heating elements. In addition if the foil has aggressive ticking you may find that these deep ticks become separation starters. So the material pulls apart faster between the ticks. The solution for this is to move a jig / table filler closer to that edge and it should solve the problem right away. In general most press operators think in terms of board feed rate in their saws or imput data into the press machine but we often have to think of membrane pressing as more of an art. To recap, 1. Whitened corners can be due to the material being too hot. Solution: Put fillers closer to the edge of the part 2. Whitened corners can be due to the material being too cold. Solution: Increase the preheat by 10%. Be sure to use heat strips to ascertain this 3. Dark woodgrains or items with deep texture can whiten easier. Solution: Put fillers closer to the edge of the part I hope that you find this post helpful and if you would like to add any tips or points please feel free to send me an email. Drying Racks for 3D Laminate components
Recently I received a call from a company who just got a press. They said they were looking for drying racks and that when asking around people recommend that they call me. I was so happy to hear this because it signifies that people know I will go the extra mile and if I dont know the answer I'll find it out. So I looked through my notes and right away found the following site which sells carts for drying thermofoil doors and other components. shopcartsusa.com Cost $325 for Drying Tower DT-50. 50 shelves 25 per side This is the price the last I checked however it may change by the time you read this post. If you are ever looking for something or need pressing assistance please dont hesitate to ask. Also if its a topic or product that you do not want me to publish on this blog you can also request that as well. Dackor does sell tools at www.dackor.com/tools however we do not currently carry drying racks Producing Shaker doors that are clean and neat are the goal. If you take a 3D Laminate shaker door and cut it open you may be surprised to find a plant in center panel. Read below to learn more.
PRODUCING A SHAKER DOOR: To produce a shaker door and then membrane or vacuum press the door companies first router out the center reveal. One common issue is that in doing so the fibers of the door open up. It can be very difficult to then get a sander in and to accomplish the desired finish. On top of that , when a PUD adhesive is applie, the PUD adhesive is about 58% water which further opens the pours of the MDF open and will show through the 3D Laminate after pressing. The ideal solution is to take a 1/8" HDF board cut to the size of the center panel and to drop it into the center of the shaker. This is the most common way companies create good looking shaker doors in the component industry. The HDF (High Density Fiberboard) can be left unsanded with the factory finish. It is important however to glue the center panel in because failure to do so will make it sound like the beat of a drum when closing the cabinet door. The center of the door can be glued in by the PUD adhesive used in the membrane pressing process. PAINTED DOORS: For painted doors, the key to get a good finish is to paint the door and then sand it to a 250 to 300 grit and then paint again. This will smooth out the surface before doing a finishing coat. PLANT ON SHAKER: For plant on Shaker, you can take 1/2" mdf and run a 1/4" to 1/4" mdf through a shaper and then miter cut and piece the parts on the door using a PUR adhesive. This reduces the milling time out of the shaker and creates a lower processed cost Shaker. It will have a reveal line on the perimeter of the door however this is a small price to pay for saved CNC milling time. CONCLUSION: If you follow the steps above you can get a better looking shaker door. For additional information please feel free to contact me for further information or further research. There are various ways to process 3D Laminates. In this article I will mention all the ways you can process 3D Laminates and also mention some common machine names used in membrane pressing and vacuum pressing.
MEMBRANE PRESSES: At the time of me writing this article, the most common brands of membrane presses in North America are Wemhoner which is sold by Stiles Machinery, Shaw Almex which is sold by Black Brothers, Italpress which has their own office, Orma, and Burkle. www.membranepress.com Advantages of membrane presses: Membrane presses typically use rubber or silicone membranes to firstly transfer heat to the components more rapidly and secondly they apply positive pressure on top of the components to press the material while the vacuum on the bottom of the press can also have suction. The pros are that the cycle times are fast and its easier to get more detail in the component under most conditions. The cons are that they membranes need to be replaced periodically depending upon the cycles ran and also based upon the parts produced. The other con would be the cost of a membrane press. They typically cost $200K to over $500K however you may find one for less or a used one. Please do keep in mind that some membrane presses are capable of removing the membrane from the machine and still operating but not all. VACUUM PRESSES:The most common brands of vacuum presses sold in North America are Shaw Almex, Italpress and Greco. If you are a maker of vacuum presses and do not see your company's info here please contact me. I apologize if I overlooked it. Advantages of vacuum presses: Vacuum presses are more affordable however they do not have positive pressure on top. Vacuum presses rely solely on the vacuum power below and they use light bulbs or heat plates on top in some machines. Most vacuum presses have longer press cycle times and do not get as much detail into the components. There are some tricks such as drilling holes in the backs of the components to enable vacuum to pull through the MDF and also some companies will score the glue line on the side of the component with a knife which breaks the seal a bit and enables more vacuum. In general, companies who produce mass components for others prefer a positive pressure membrane press with or without the membrane in lieu of a vacuum press. Vacuum presses are an inexpensive way to get in the business however they are more suited for companies who use the components internally for their own cabinets or fixtures and less suitable for companies who mass produce components for others and whose livelihood is attached to selling components due to the longer press cycle times. FLAT LAMINATION: 3D Laminates or vinyls can also be flat laminated either by a flat lamination machine utilizing PUR adhesive typically. These machines are designed for fast flat lamination. The other way to flat laminate is by a nip roller using a 2 part epoxy glue. PROFILE WRAPPING: 3D Laminates can also be processed by profile wrapping moldings MITER FOLDING Miter folding is where material is flat laminated or membrane pressed to a component with a v groove in the back of the part. A line of glue can be ran in the groove and then the part is simply folded to create a seamless fold. The vinyl acts as a hinge. Please note that white lines can appear on the fold with vinyls which is caused by various reasons. Companies use wooden blocks to rub or heat guns to remove the white lines. Some laminate manufacturers can produce vinyl so that they will not whiten when folded. HAND LAMINATION: 3D Laminates can be processed by contact cement, peel stick or laminate backed for hand applications. The laminates are not specifically made for this type application so this is the exception rather than the rule. CONCLUSION: This post is just a teaser and does not get deep into the topics. If your company is a processor in North America and has technical questions you can contact me for more detailed information, tips and tricks. Manufacturers of 3D Laminates know that the product has many advantages as compared with HPL and other surfaces. 3DL's impact resistance can be far superior to most laminate surfaces and the taber abrasion can be extremely high especially with solid colors whitch are homogeneous. But how about scratch resistance? In this article I'd like to discuss some obscure tricks on how scratch resistance is obtained with 3DL that most companies don't share.
Firstly, each company has claims that their product is more durable based upon a unique or proprietary lacquer. Although each company has its own formulation the real secret is in tweaking a combination of lacquer and texture. Also gloss level of the print layer and lacquers can play a roll as well as the color of the print however this article is meant to focus on a specific subject of texture which is one of the biggest factors that contribute to scratch resistance of 3DL. OK... so to start.... The most common lacquers are polyurethanes or polyurethane combinations. Applying lacquer is key to protect the top surface's hills and valleys and provide hardness to the surface. This sounds like the end all be all solution however in reality if a sharp objects digs into the peaks (hill tops of the texture) in a certain way then its irrelevant as to how much or what type top coat is applied. Think of your carpet and running your foot over the carpet. The carpet is not damaged however you moved the carpet strands in a different direction it gives the appearance of difference and that is at the basis of what a surface scratch really is. So if you think about it, a micro level, scratches to most surfaces are either a displacing or a removing of surface area. In theory a top coat will protect a scratch from occurring however in practice its only one component to creating a scratch resistant surface. In general a higher texture combined with lacquer is a way to get an overall scratch resistant surface. Some woodgrain designs, for example may have a lighter texture from one supplier due to market demand and when you try to scratch it, the appearance is that that supplier's product is less scratch resistant however upon closer inspection you may find that if they put the same texture on they would get equal scratch performance. So its very difficult to judge scratch resistance between supplier if you are not measuring apples to apples. Since each supplier uses different textures and different lacquer/gloss level combos it also may impact the scratch resistance performance in that single color. Another point is in the texture layout. Imagine a texture on a microscopic level and when a sharp object moves in a straight line it is removing hills on the tops of the texture. If the texture is spaced in a certain way to make the hill tops more random it can trick the eye into not seeing the scratches as easily. This can also be achieved by making different heights of texture in the emboss. Imagine at certain pressure points only knocking off a certain height of textures however with just slight more pressure it may finally break into the next layer of texture hills. Its another clever way to enable an object to glide across the top of the texture yet not see the scratch as easily with the naked eye. Surprised by this observation? As with any product, the expertise in product design combined with the marketability of its appearance all come into play in order to achieve a result. You may in fact, start to see all the complexity that goes into creating a 3DL. You will also notice that dark colors show scratches more easily. Lighter colors absorb the light and blind your eyes to the scratches that are on the surface so to speak. So, in conclusion, there are a variety of ways to make a scratch resistant 3DL... Lacquer, quantity of texture, color of design and texture layout on the microscopic level. The items just mentioned must also be used in proper combos to create the best affect. One potential problem in pressing is called ghosting or shadowing. This is where the center of the part seems to have a darker section or where it looks different than the edges of the part.
This type of manufacturing defect can be fixed by adjusting the settings and is not a vinyl or glue issue.Essentially ghosting is caused by a change in the surface texture. This is caused by the vinyl becoming over stretched on the edges and the center part of the component which is discolored is a section of the vinyl that was not stretched at the same rate as the other areas. Typically this issue only happens on membrane presses and not on vacuum presses. The reason is that the membrane is trapping the vinyl down to the door. Raising the membrane for a vac to get the vinyl stretching evenly then lowering the membrane to finish up the detail. Various presses have different functions so this needs to be discussed. In cases where your membrane press does not have the ability to raise the membrane for a vac stage you can try to move the parts further from each other. This gives more vinyl between each component and can reduce the over stretching. If both cases above do not work please feel free to contact your laminate sales rep and they will get a tech expert to help fix the issue. It can be solved. Introduction
As a manufacturer of 3DL Doors or components you are probably used to seeing color matches of solids and woodgrains. On occasion you may have even had a manufacturer to color match some item for you. In this article I will delve into the technical side as it relates to color matching and color control. I will explain more about why different sources of light affect the color and cause metamerism and I’ll mention a lot of interesting facts such as how the size of a sample can actually change your perception of the color. Since most people selling doors, components or Kitchens utilizing 3D Laminate thermofoils are selling color I think that there may be new and interesting facts as it pertains to colors. Appearance There are three things that have the biggest impact in matching a 3D Laminate; the print, the texture and the gloss level. One interesting point is that under normal viewing conditions a sample with a higher gloss level will generally appear darker than a sample with a matte surface. This means that when matching colors it is critical to not only match the design but the gloss level needs to be similar. It also means that if you are working with two different products such as a melamine board and a 3D Laminate which has a different texture you will need to make some consideration in regards to how the different textures are contributing to the color. When I visit a customer or when I am managing our sales staff I ask questions such as : 1. Who is the decision maker? Purchasing, Management or their client? 2. Does the decision maker have a window in their office and to which side is the window facing their desk? 3. Does the decision maker have flourscent lights or incandescent? 4. Does the decision maker hold the samples up in front of their face or look at them laying on their desk? 5. Does the client want ticking texture or a different texture than the target color? The above questions are critical to being a good color matcher because all of these small things play into the quality of the match as I’ll describe below. Texture The surface texture will dramatically change the gloss level and affect the perceived color. An interesting pont is that the human eye is more critical of any color difference in a smooth texture than in a rough texture. So if a customer asks us for a smooth emboss on a solid color then it means that the accuracy will be more fragile. When matches are made to HPL (High Pressure Laminate) or TFM (Thermofused Melamine) typically there are various things that cause the materials to look differently. Firstly the process of impregnating papers with melamine resins can create a bit of a haze. Secondly the texture used on the press plates is often different that the embossing rollers used in a 3DL (3D Laminate). This affect is called metamerism. There are various definitions of metamerism however I feel the most accurate for our purpose is: “a metamerism occurs when the color standard and the submit do not match under all lighting conditions. This means that a solid color fabric when viewed under two different lights in a commercial light box, will appear to cast two different colors.” Texture is the biggest refractor of light and this is the key source of metamerism. So the key point here is that the target match (paint, TFM, or HPL) typically is different than the surface texture of the 3DL so the match complication is dramatically increased. So for any manufacturer of steel, laminate, paint, carpet or whatever surface manufacturer, the difference in processes between manufacturers is a key complication in color matches. Color – The Fundamentals Since 3D Laminates are a plastic for you to better understand colorants it first requires basic knowledge of how color works for plastics. Color is not an absolute property as the perceived color of an object is dependent upon three elements. The elements are Illuminate, Observer and Object. Illuminant The illuminant used will affect the perceived color dramatically. Perception of color is unique as the human eye perceives colors differently under various light sources. The perceived color under a fluorescent light is different than that perceived under an incandescent light, and they will both be different to that perceived in daylight. Keep in mind that daylight is one of the most uncontrolled and variable sources of light, and will vary with time of day, weather, orientation, etc. Observer Perception of color requires an observer (either human or instrumental). What most people are unaware of is that every individual has a unique and different sensitivity to color that may be biased slightly towards a specific color. So they may be unaware that they believe a color is a good or poor match however the general population may in fact that it is a good match. This does not mean that they will always get it wrong but it can mean that as an individual you may perceive maples or yellow toned colors inaccurately however for cherries or solid whites your eye is highly accurate (based upon the populace). An interesting fact is that Men are approximately 16 times more likely to be color deficient than women. Approximately 8% of men and 0.5% of women have some degree of inherited color deficiency (200 million people worldwide). Red-green color deficiency is a hereditary disease, carried by the X chromosome of females. For this reason the daughter of a color deficient father can pass it to her sons. Women have two X-chromosomes and one defective X chromosome will be compensated for by the other non-defective. The chances of having two defective X-chromosomes are small. Aside from men being 16 more times likely to be color blind, researchers have also found that there are in fact differences between men’s eyes and female’s eyses. As you may know humans have 3 different type of cone cells in our eye. Our eyes perceive color basically the opposite of a TV set. On a TV there are different color dots of red, green and blue. In the eye, con cells also have three different photo pigments that are generalized as red, green and blue but actually they are yellowish green, green and bluish violet. What researchers have discovered was that over 50% of all women posess a fourth photo pigment that makes women more adept at detecting subtle spots of red light. So in conclusion, women (on average) are superior at more accurately detecting colors. Object Most are unaware that the target or object may appear to be relatively constant but in actuality the color perception can vary within an object. So large areas of a color appear brighter than small areas of a color. If a target is a solid white HPL that is 2 square feet the absorption of light will affect the perception to make the sample appear lighter than if a 3” X 4” color sample is used. That is why factories who produce color maintain internally strict color matching procedures such as the size of samples they are evaluating. This is called (the area effect). The next time you show a client your color match try to present samples of the same size so the customer can more accurately perceive the colors. Colors will actually appear duller when in front of a bright background than when in front of a dark background. This is called (the contrast effect) The next is that colors will appear different when viewed from different angles or when illuminated from different angles. This is called (the directional effect). So image when a sales person presents a color match to a client and the light source is above head whereas another client may have a lamp on his desk or be sitting by a window. Imagine how all of these can affect a client’s perception of the quality of match. Measuring color Color measurement can be carried out either by what is called a human colorist or by instrumental means. Using a human provides exceptional differentiation between colors but is limited in how this information can be transmitted to others and used as a control mechanism. Instruments sacrifice some color differentiation, but have the advantage in that they are reproducible every time. Instruments map onto a “color space” to provide the numbers or symbols for comparison and specification. Hue Hue is the basic color and is generally divided into a color wheel which ranges through 5 principals that include (red, yellow, green, blue, and purple) and all the variations in between. A simple color wheel is shown below. The location of a color around the wheel obviously defines the ‘hue’ of the color. Lightness (brightness or value) Lightness is the vertical axis and runs from light at the top to dark at the bottom. The location of a color on the lightness scale defines how light or dark the color will be. Saturation (chroma) The saturation of a color is how far away from the light axis it is – colors which are far away from the value axis are pure colors and those close to the value axis tend to be grayer. Saturation defines how pure a color is. Various color measurement systems have been developed in order to locate the 3D space. The very first system was the Munsell system developed by American artist Albert Munsell and this is known as “the rational way”. They use indicators such as 7.5PBYR 6/6. This indicates a purble blue hue but closer to purple with lightness of value 6 , a saturation of 6. This is a pure visual eval system. The next is the CIE (International Commission on Illumination) of the Yxy color space, the L*a*b* color by CIELAB and the Hunter Lab color space. In the L*a*b* system which is typically used by 3D Laminate manufacturers to color control colors it uses the following: L* defines the lightness/darkness of the color. a* defines the greenness/redness of the color. b* defines the yellowness/blueness of the color. The combination of L*, a* and b* can be used to define the relationship between colors and as a quality control tool by most laminate manufacturers.Please note that “E” is the average of L, a and b so it is common to have the E number listed as well. Color measuring instruments The two most common types of machines for the measurement of color are the tristimulus colorimeter and the spectrophotometer. The tristimulus colorimeter is a machine that directly measures the sample color and uses red, blue, and green receptors. This is simliar to the human eye. The major disadvantage with this type of machine is that the results are only meaningful under the specific illuminant used for the machine. Different colorants respond to different lights in different ways (a phenomenon known as metamerism as mentioned earlier in this report) The spectrophotometer measures light across the whole of the visible spectrum to produce the full reflectance curve that can be processed to give the tristimulus values and chromaticity for any desired illumination. The full reflectance curve for various colors can be investigated to determine if metamerism will be present under varying illuminants. The use of spectrophotometers requires knowledge of the type of machine being used and the detailed geometry of the machine – the various types available can detect or exclude texture and gloss levels and even take into account special effect finishes such as mica or flake colorants. Measurement problems Metamerism: Color perception of many colorants is often affected by metamerism. This is where colors that may appear the same under one set of lighting conditions will appear different under a different set of lighting conditions. Typically in our industry metamorism takes place between fluorescent light sources and natural sun light since most manufacturers using the 3D Laminates do not have an International Standard Light box on premises. Temperature: Color is often ‘thermochromic’ and most colors will change with the temperature at which the measurement is made. Humidity: Color is often ‘hydrochromic’ and most colors will change with the humidity at which the measurement is made. Methods of Coloring Plastics 3D Laminates Plastics are typically colored by the following methods of printing, painting, pigments, internal colorants, dyes and surface colorants. For pratical purposes please note that the color of a 3D Laminate solid color is in the base calendered film whereas in a printed woodgrain the color is adjusted by the printing primarily using 1 to 5 print cylinders. This process is known as gravure printing where the print rollers (rotate) dip into an ink pan and rotate while applying the ink to the print layer. Printing can be done by direct to a print layer or via reverse printing to a clear transparent print layer. The average amount of printing cylinders is 3 and each cylinder must turn in register to one another in order to give the print clarity. The second way to adjust the color is through the base layer which can affect the darkness or lightless behind the print layer. Summary I hope that after reading this post you have picked up something new in regards to color, perception, procedure or that you have a better feeling for how humans interact with color. In some small way I hope that this article can influence how you sell color or how you may be more careful of conveying color to your client. Try to be observant of your customer’s light source, to the size of the sample and pay specific attention to the texture of the surfaces. As long as your X chromosome isn't defective and you follow the principles above you can have a better understanding of color and especially matching of colors. Originally published: May 20, 2009
This post is in honor of Craig's years of dedication to the industry we all love. My name is Craig Thomas, Project Manager for Daubert Chemical Co., and I have worked with companies helping them with the thermoforming process for 20 years. Mark Viers and I have known each other for years as friends and associates while we both serviced the thermoforming market from different sides of the supply chain. So when Mark called me and asked if I had any tips for companies that spray membrane press adhesive I agreed to share some tips for common questions that have come up over the years from companies that spray PUD (polyurethane dispersion) for thermoforming. Good spay techniques are essential to producing a quality pressed product. What equipment should I use? To achieve a smooth even spray I always recommend a HVLP gun, using a .050” to, 065” tip, with a pressure pot system. A cup gun is OK for small jobs but for extended use a pressure pot. You kind buy a pressure pot as small as 2 quarts. What should I do if my guns continues to clog up are drip when I release the trigger? These adhesives are sheer sensitive which means that if the adhesive is subjected to forcing the adhesive through a gun at high fluid pressure it will tend to “ball up” or string causing clogging at the tip. Clean the gun and hose thoroughly. Make sure your needle is open to the point that you have full trigger. Now set your pressures at 15 to 20 psi for the fluid side of your gun and the atomization (air) pressure at 50 to 60 psi. These settings will allow the adhesive to flow through you equipment with the least amount of sheer. An easy way to see if your fluid pressure is corrct is to pinch the air supply to the gun closed and pull the trigger. The adhesive will come out in a stream without atomization air. The stream should come out 2 to 3 ft like a garden hose. If you pressure is too high the stream will look a garden hose with a pressure nozzle. Also, if you have a filter on your pik-up tube in the pot, I recommend you remove that and strain your adhesive while putting it into the pot. Now you know why I recommend a pressure pot system. So you can make these important improvements. Can I stack my part when spraying? Yes, as long as they are the same size. This will save glue due to less overspray. What is the best way to spray my parts? You need to spray the edges with 2 or 3 goods coat to insure enough adhesive remained on the surface and did not dive-in to the routed edge of the board. You do not need to let the adhesive dry between coats. Now you can spray the top surface with 1 even coat. It is very important to hold the gun perpendicular (90 degrees) to the part while spaying. What is the correct dry time for the adhesive? You need to “rack” the parts for drying and rack from top to bottom so not to knock any debris on the wet glue from stacking parts above the previous sprayed parts. The parts should be dry to the touch in 15 minutes and ready to press. The higher the humidity in the shop the longer it take to dry. Those are answers to some of the most common questions I have received over the years. There were many more but because of time and the possibility of boring you to death, I will stop here |
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