FAQ

The Hafner LCD printer allows you to use castable resins for very high-quality printing.
The Hafner LCD technology also features X and Y axes that are larger than most, often much more expensive, DLP printers currently available while achieving the same level of quality.

We want to bring the Hafner casting quality standards to the 3D printing sector and have therefore carefully selected only the best components.
Our experience has shown that the printing results from an LCD printer are 60% reliant on the components used. Among the remaining 40% the image editing software is an important factor.
The quality of the printer is dependent on the quality of the image it has to work with. This is known as the “slicer software”. It is for this reason that we have developed our own Hafner software that specifically works to our requirements. An additional, important factor is the UV resin used for printing.

The speed of a resin printer is primarily dependent on the type photoinitiator used in the resin. For example, the light intensity of a DLP-UV projector is in the range 2200 to 3200 lumen. This means that the same, identical resin will deliver different printing results with different printers and greatly influences the printing speed based on the curing layer.
The Hafner Precision Legend printer can theoretically print 36 mm / hour. However, there is always a tradeoff to be made between speed and quality.
Resins designed for speed contain many UV reactive materials. This allows these resins to be printed quickly in steps of 50 to 100 microns. If, however, you prefer to use casting resin for higher quality results, then a photoinitiator that does not trigger a chemical reaction with the embedding compound powder is required. This photoinitiator needs more than twice as long to cure as a resin designed for speed. We also require a special photoblocker in order to control the curing depth, prevent overcuring and the Z height reduced to 25 microns. Achieving the same height of 36 mm with our special casting resin therefore takes up to 4 hours.

The light penetrates the display from below (just like a TV) and is generated by long-lasting and energy efficient UV LEDs. These LEDs emit a bluish light at a wavelength of 405 nm that activates the chemical reaction required to cure the resin.

All light sources, whether a light bulb or natural daylight, contains some UV light. The plastic hood on the printer filters 99% of UV light that strikes it. The remaining UV light that passes through causes the resin to cure continuously, albeit very slowly.

A resin printer should be put operated in the darkest possible area of a room. Either in a dark corner or in a separate dark room.

Printing with resin uses a chemical liquid. You should therefore observe the information provided in the datasheet for the resin you are using.
We recommend using the printer in a well ventilated area and with an extractor if necessary.

All light sources, whether a light bulb, neon strip light or natural daylight, contain some UV light. The plastic hood on the printer filters 99% of UV light that strikes it. The remaining UV light that passes through causes the resin to cure continuously, albeit very slowly.

Any shaking that occurs during the printing process can later appear as a visible line along the Z axis or even as small misalignments in the component.

The image is projected from the LCD display upwards towards the printer platform. The light passes through the transparent FEP film in the resin tank. The tank contains the UV-active resin which hardens in the areas where the light is projected and adheres to the overhead printer platform. This process is repeated layer by layer until the finished component has been printed.

Our LCD printing process uses a high resolution LCD display to emit tiny points of light called pixels that are just 47 microns in size. Lined up together, these produce the X/Y area. When compared to the laser printing process (known as the SLA process), SLA has shown itself to be expensive and required significant maintenance. In this process, the laser is mounted in a fixed position, meaning that the emitted laser beam must be guided in the X and Y axes by two small movable mirrors, called galvanometers. Both of these small mirrors require two additional electromotors to move, which represent further potential sources of error and unavoidably experience mechanical wear over time that reduces mechanical precision. Over time, dust also settles on the galvanometer mirrors. This cannot be cleaned off by the user. Expensive servicing is then necessary. With an LCD printer on the other hand, the user can easily clean dust off the display using a cloth - similar to cleaning a mobile phone screen. This is primarily what differentiates our printing process from other resin printers. Our process also does away with the need for an expensive projector, such as those used in the DLP process.

The working life of a display is based on operating hours. The number of operating hours depends in turn on the type of resin used. Depending on the resin and application, each layer is illuminated for anything between 2 and 14 seconds. Adding together the illumination times for each layer gives you the display’s number of operating hours. The lifespan of a display can therefore vary between 400 and 2000 hours of illumination. Attention: The operating hours of the display are not to be confused with the operating hours of the printer!

No matter how good the printer and software may be: If the UV printing resin cannot be cast, then 3D printing is just a gimmick and a nice-to-have.
Not all resins are the same. They must be adapted to properly develop on a printer’s illumination unit. The same resin can deliver differing results on two different printers.
We have therefore adapted our own UV resins and cauterization process using a plaster bonded embedding compound to achieve optimal results with our printers and ensure that the resins themselves meet our internal standards. We are working to continuously improve our resin.

This depends on the size of the parts and their geometry as well as the amount of support required. On average, a bottle of resin (500 g or 500 ml) should be enough for 300 - 400 solitaire rings.

The resins are a liquid chemical. You should therefore observe the information provided in the datasheet for the resin you are using. This will describe the proper way to handle the resin and any safety information that you observe.

Substances within the resin can evaporate of a period of several day if the resin is not stored in a airtight container. We therefore recommend returning the resin to a appropriate container after printing. Please use the supplied resin paper filter when refilling the resin bottle.

Deposits can be left in the resin tank each time you use the printer. This is often a result of there being areas where “sufficient” supports were not added in the Hafner software. This causes these areas to adhere to the base of the resin tank (FEP film) or even float around freely in the resin. In order to avoid subsequent printing errors, we recommend filtering the resin after every use.

Used resin can always be returned to the original resin bottle. Please use a filter! Small tip: If you want to be really careful, then you can order a second resin bottle for storing used resin. Next time you want to print something, you can then first fill the tank using the previously used resin before topping up with fresh resin.

Filling the tank with 2 to 3 mm of resin so that the FEP film is fully covered will be more than enough. The tank can serve as a spirit level to help you ensure the printer is positioned on a level surface. This amount of resin is enough to print e.g. 10 women’s rings.

When the printing platform moves downwards into the resin, the resin is displaced.
If the tank is too full, then resin will overflow out of the tank.

A rectangular air grille is located on the rear left side of the enclosure. Here, a fan guides the air inside the “closed” printer through a filter. The starter set contains a black cube with the same dimensions and a small bag containing activated carbon. First place the bag of activated carbon into the open cube and then place onto the ventilation grille with the magnet on the cube facing downwards. The magnet keeps the filter in place.

A rectangular air grille is located on the rear left side of the enclosure. Here, a fan guides the air inside the “closed” printer through a filter. The starter set contains a black cube with the same dimensions and a small bag containing activated carbon. First place the bag of activated carbon into the open cube and then place onto the ventilation grille with the magnet on the cube facing downwards. The magnet keeps the filter in place.

Using a fan, the printer generates a flow of air that causes it to pass through the activated carbon filter and is then guided to the base of the printer to cool the electronics. Please ensure that the cover on the printer housing is always closed.

We recommend replacing the activated carbon filter every 300 operating hours.

The printer cover should be kept closed to prevent resin from drying out due to any scattered light and to prevent dust getting in and disrupting the process.

The cover can be opened during printing. However, be aware that any shaking or jolts can result in visible streaks in the finished part.
External scattered light and dust can also affect the quality of the print.

Whether or not a primer is required depends on the type of resin. Please consult the information about the different resins. The primer functions as an additional surface to ensure that the resin has a sufficient hold when curing. It can happen that a piece of printed resin comes loose during the printing process and falls into the tank. In order to ensure sufficient adhesion of e.g. castable resin, we recommend applying a thin layer of primer to the printing platform and curing this with a UV light before starting the printing process. Please see our To-Do videos:

If you have inadvertently failed to position a sufficient number of supports, or forgotten entirely, then the last layer to be illuminated during the printing process cannot be lifted from the FEP film and remains attached to the base of the tank. In order to clean the tank and FEP film without causing damage, we recommend using the cleaning function. Fix the tank and resin contained within it into the indicated position. The cleaning function can then be started; see To-Do Videos:

If insufficient support was placed using the software, a layer can become stuck on the bottom of the tank (FEP film) instead of the print platform. In order to remove these layers from the FEP film, we recommend using the “cleaning function”, see To-Do Videos:

Failed prints can also float in the resin as residues. These can be removed by filtering the resin.

In the event of a power cut, the printer will behave just the same as if you had suddenly turned it off yourself. If this happens during the printing process, the printer will simply stay in its current position unpowered. As soon as the power returns, the printer will travel into its home position as if it had been restarted. To avoid printing errors due to power cuts, we recommend operating a UPS (uninterruptable power supply).

If the power fails during the printing process, the printer will simply stay in its current position unpowered. This interrupts the current print, which cannot be continued. The entire printing process must be started again from the beginning (don’t forget to release the printing platform from the unfinished 3D print beforehand). Print files stored on the device are not deleted if the power fails and can be reprinted as often as needed.

To avoid printing errors due to power cuts, we recommend operating a UPS (uninterruptable power supply).

Please check your CAD file. This error is usually caused by areas that are not fully connected to other areas, an erroneous “Boolean operation” or a corrupt STL file. Our Hafner software allows you to go through each “slice” layer one by one to see if e.g. there are any missing layers.

If insufficient support was placed using the software, a layer can become stuck on the bottom of the tank (FEP film) instead of the print platform.
In order to remove these layers from the FEP film, we recommend using the “cleaning function”, see To-Do Videos :

Failed prints can also float in the resin as residues. These can be removed by filtering the resin.

Any amount of pressure applied to the film will leave traces that can later affect print quality. This can cause a hole to develop in the film and the resin spill out.
In order to clean the tank and FEP film without causing damage, we recommend using the cleaning function. Fix the tank and resin contained within it into the indicated position. The cleaning function can then be started; see To-Do Videos:

Any amount of pressure applied to the thin film by sharp objects, e.g. tweezers, will leave traces that can later affect print quality. This can cause a hole to develop in the film and the resin spill out.
In order to clean the tank and FEP film without causing damage, we recommend using the cleaning function. Fix the tank and resin contained within it into the indicated position. The cleaning function can then be started; see To-Do Videos:

Cleaning the tank with paper towels leaves small scratches on the FEP film. We therefore recommend cleaning the tank as shown in our video:

Please watch our video about cleaning the tank. This will show you the correct way to handle and clean the resin tank:

The word “Teflon” is a protected trademark name for a type of non-stick coating. “FEP” (fluorinated ethylene propylene) is a type of transparent plastic film widely used by resin 3D printers.
Standard FEP films can hold a water droplet in shape up to around 40%. This property is known as the lotus effect. The lotus effect refers to the wettability of a surface. We, however, use a special type of film! The high quality of our special film keeps water droplets in shape up to 60%. This results in significantly less removal force between required in comparison to other resin printers, which has a visible effect on print quality.

During the printing process, the hardening resin layers and contact with the FEP film cause wear. This wear causes the film to become cloudy. This clouding causes light to be more diffuse, thus affecting the sharpness of edges and precision. We therefore recommend replacing the film if it begins to appear cloudy or has pressure damage.

This depends entirely on the degree of cloudiness or damage on the FEP film, which in turn depends on the resin used. Castable resins, for example, do not generally contain any aggressive fillers. This means that the film stays in good condition much longer than with resins used for mechanical applications. These usually contain abrasive filling materials that have an effect like sandpaper on the film, making it become cloudy much more quickly.

You can buy our special films from our distributors. The high quality of our special film keeps water droplets in shape up to 60%. This results in significantly less removal force between required in comparison to other resin printers, which has a visible effect on print quality.

To do this, place a white sheet of paper on a flat surface and put the resin tank on top. Fill the tank with water. If the film has not been perfectly positioned, the sheet of paper will become wet at the point of the leak. After testing, ensure that you clean the tank using compressed air. This prevents any water droplets from being left behind that may become mixed in with the resin.

The display has a protective layer of glass, similar to that used on your mobile phone display. If resin gets on the display, carefully apply a few drops of IPA (isopropyl alcohol) to the affected area and leave to soak for a few minutes. Then, using a plastic scraper, try to remove the loosened resin. Repeat the process again if necessary. If you are still unable to remove the resin, repeat the process using acetone instead.

Please see the instruction manual for information about the contents of this set. All components and their functions can be found there. Our tutorial videos can also help.

The scraper you receive in the starter set is used to help remove freshly printed objects that are stuck to the printing platform. Please see our tutorial video to find out how to correctly remove printed components:

The blade on a box cutter is very flat and sharp. This means that you can more easily get it under the part to remove it. However, care must be taken as you can easily injure yourself using a box cutter. We therefore recommend using the included scraper.

The Z axis is the only moving part of our 3D printer, meaning that maintenance requirements are minimal. We recommend using a silicone lubricant on both running rails of the Z axis every 6 months. If one of the two rails starts to run dry, you will be able to hear the bearings squeak each time the Z axis moves. Please listen out for this noise.

We recommend using a silicone lubricant on both running rails of the Z axis every 6 months. If one of the two rails starts to run dry, you will be able to hear the bearings squeak each time the Z axis moves. Please listen out for this noise.

The LCD display experiences wear and is therefore considered a consumable. This relates to the number of hours where illumination was active, not total operating hours of the printer. The liquid crystals in the display degrade over time due to the UV exposure. The first pixel failure can be expected from around 400 hours of illumination.

You can easily replace the LCD display yourself. Please see our video tutorial at:

The starter set includes a matching Allen key for each type of screw used. These are needed for adjusting the printer platform and for replacing the LCD display.

The platform is calibrated by us in the factory. This means that the printer is delivered ready to use. It is not necessary to recalibrate the platform. If you order a second platform, however, this must be calibrated to the your printer. Instructions on how to do this can be found in our video tutorial:

Please follow our video tutorial:

Cleaning removes resin residues from the freshly printed object.
This is important for ensuring details are visible as resin residues can often fill small gaps such as holes or recessed text. If exposed to light without being cleaned, these recessed parts can become sealed over. This is an extremely important step when using castable resins in order to avoid chemically damaging the plaster when embedding.

The alcohol acts as a solvent for washing off the unhardened resin from the finished piece. We recommend using methylated spirit with our Hafner resins as this is not as aggressive as IPA (isopropanol).

We recommend using methylated spirit with our Hafner resins as this is not as aggressive as IPA (isopropanol).

If the part is still feels a little sticky after cleaning, the alcohol needs to be replaced. We recommend using two separate alcohol baths - one for pre-washing and one for post-washing.

This is important for ensuring details are visible as resin residues can often fill small gaps such as holes or recessed text. If exposed to light without being cleaned, these recessed parts can become sealed over. This is an extremely important step when using castable resins in order to avoid chemically damaging the plaster when embedding.

If the part is not properly cleaned, resin residues can remain and cover things such as holes, indented areas or edges. This means there is more resin on a particular area that will harden when exposed to light and thus negatively affect the precision and detailing of the part.

We recommend using a professional programmable cleaning bath that can ensure fast and even cleaning by circulation of the cleaning fluid. The freshly printed parts should be exposed to the cleaning fluid for as short a time as possible.

Yes, printed parts can be washed by hand. We recommend using two separate alcohol baths - one for pre-washing and one for post-washing. If washing by hand, please use the gooseneck flask included in the starter set in order to ensure the spray also gets into the difficult to reach areas.

The gooseneck flask helps ensure the spray also gets into the difficult to reach areas.

The alcohol cleaner should be disposed of in accordance with local regulations.

Castaway resin contains 60% wax. This makes freshly printed objects feel very soft. Only after subsequent exposure to UV light will the monomers harden together with the wax to give the part its final firmness for further processing.

If freshly printed parts still feel sticky after cleaning, then they have not been sufficiently cleaned. You are feeling the resin that is stuck to the surface of the print. Please clean the object again, using a fresh alcohol bath if necessary.

Our 3D printer is designed for resins that respond to wavelengths from 385 nm to 405 nm. You need the required for the resin used in order to cure your 3D prints. Please follow the instructions for the resin you are using.

Showmaster = 405 nm

Copycat = 405 nm

Cast Away = broad spectrum UV! (See below).

Curing castable resins is key factor in ensuring good casting results. Our experience has shown us that resin components that have not fully hardened are primary cause of poor results. We therefore offer a special UV oven that can operate at different wavelengths, 365nm and 405nm, to ensure components are properly cured.

The resins you are using are UV-active. Areas of resin exposed to UV light by the 3D printer will harden. The printer uses very small amounts of UV light to form perfect layers and detailed surfaces. After cleaning with alcohol, all parts should be exposed to an intensive UV light source in order to fully cure them.

The duration of the exposure depends on the intensity of the UV light source used. Please follow the instructions provided by the manufacturer of your UV curing oven. The same applies for the resins. Different resins have different curing times depending on their composition. Please see the included datasheet for your resin.

Shrinkage occurs due to a chemical reaction between the different components of the resin. There are 3 factors at play here.

1. Shrinkage of each individual layer during the printing process.
2. Shrinkage when cleaning with alcohol.
3. Shrinkage during UV exposure and the curing process.

We have calibrated all of our Hafner resins to our printer in order to ensure the best possible accuracy. Please make sure to carefully follow the production process in our instructions.

The most important factor affecting shrinkage is the UV exposure. For the best possible precision, we recommend using our UV curing oven. Our resins have been calibrated to the precise UV value used by this.

The support structures are primarily used to keep your printed component in position on the printer platform. Please bear in mind that the printing process starts from the top and the weight of the printed part must counteract the force of gravity. If your printed part has overhanging sections, these will need a support placed at the lowest position. These areas are indicated in the Hafner software.

The support structures are primarily used to keep your printed component in position on the printer platform. Please bear in mind that the printing process starts from the top and the weight of the printed part must counteract the force of gravity. If your printed part has overhanging sections, these will need a support placed at the lowest position. These areas are indicated in the Hafner software.

You have two options here:

1. Using wire cutters, cut off the support just before the point at which it comes into contact with the printed part so that there is just small part remaining that can be sanded off. If you cut the support off too close to the object, small parts from the object itself can come off which would then need to be subsequently filled.
2. The second and much more convenient solution is to use an “ultrasound cutter”. This is an extremely sharp blade that uses ultrasound vibrations to separate and cut off the supports upon contact.

In the case of holes or incorrectly printed points, simply fill the gap with a drop of the same UV resin and cure in the UV oven. The already cured area will be seamlessly bonded to the freshly applied resin. Ensure to clean the repaired parts again according to the instructions.

This is a special property of our Cast Away resin. It allows the user to easily see when the chemical components in the resin have fully cured. Only once the colour has turned to blue is the 3D print castable. If any areas of green are still visible, then this is an indication that the piece is not yet fully cured and then a casting fault could occur.

Our Cast Away resin is 60% wax, a percentage of which consists of a special blue wax powder that is mixed into the resin. If you see blue deposits in the printed item, then this means that the resin was not shaken sufficiently and the wax particles not homogenously mixed throughout. Fortunately, this will not lead to any quality issues during casting.

The Cast Away formula contains both liquid wax and wax powder. This way, the wax can be removed using the lost wax process. Please pay attention to the burnout curve and information on the burnout process for our Cast Away resin.

Please shake the bottle for 10 minutes to ensure that all components are evenly mixed.

We recommend purchasing a laboratory mixer that rotates the resin bottles on rollers around their own axis.

You receive instructions on how to print with our Hafner 3D printer. These instructions make use of our devices. Furthermore, using our devices we are able to guarantee that they meet all requirements. It is a good idea for you to use the same devices that we use ourselves.

You can attach the printed Cast Away parts to the wax tree as normal with your standard setting wax. The high wax content of our Cast Away resin means that is forms a good bond with standard wax.

In order to speed up a clean burnout of the resin in the mould, it is advisable to use thicker sprue channels than normal. This ensures that oxygen and heat can reach the resin more quickly and thus ignite and burn it out sooner.
The trunk of the cast resin tree should also be thicker. You should also consider the need to create smaller casting trees.

The more resin models on a tree, the longer the burnout process takes. For example, it is not recommended to print the entire sprue channel with the model itself. This would mean that during the burnout process the model itself would ignite later and leave residues. As a guideline, consider having at most 10 models on a single casting tree. For thicker signet rings, this number should be reduced or the burnout process lengthened.

The more air, and hence more oxygen, that can circulate during the burnout process, the better the results. A 3D print located at the upper end of the tree may not receive sufficient air (oxygen) and ash residues could be left behind.

Not every burnout furnace is the same. This means differing results are achieved when burning out wax containing resins. Ultimately, it is down to the amount of oxygen circulating in the air in your furnace. Gas-powered furnaces achieve better results than electronic furnaces. We recommend that you first request a 3D printed sample from us in order to carry out testing before making your decision.

This is not necessary with our Cast Away resin. You can use the cuvette as normal with the opening at the bottom. However, you should use a corrugated burnout plate to ensure sufficient air can circulate. Ash residues can remain behind if insufficient air is available.

Like wax, the resin turns liquid only at a high temperature and runs back into the mould instead of out of it. If it remains in the form, it can begin to boil while still volatilizing. This reaction will damage the plaster and be clearly visible later as a casting error.

Selecting a suitable embedding compound is another important factor. We recommend Prestige OPTIMA from CERTUS. This can withstand temperatures up to 830 °C and is also able to reproduce fine details. It can be worked just like normal embedding compounds and can therefore be integrated into the normal process. A key factor is the addition of 2-3% boric acid. This gives the embedding compound an increased hardness and thus reduces its absorption properties.

The mix ratio is as follows:

After embedding under vacuum, the cuvette should not be moved for 90-120 minutes.

We recommend adding 2-3% boric acid. This gives the embedding compound an increased hardness and thus reduces its absorption properties.

The mix ratio is as follows:

The burnout curve for resin is different to the conventional curve used for wax. A higher maximum temperature of 780 °C is used. This temperature should be maintained for at least six hours. If there are several models on the tree, it is recommended to maintain the temperature for eight hours.

The more cuvettes in a furnace, the less oxygen is available to each one. Unlike injection wax, wax-based resins require much more oxygen to burn off the resin components. If there is not enough oxygen available, the printed parts cannot burn away and ash residues will remain behind that will later result in visible casting defects.

It is important to properly follow all steps in our casting instructions. You can read about most mistakes at the following links:

• Why should wax sprues be twice as thick than normal casting sprues?
• Why can I not print the sprues at the same time?
• Is it better to attach lower down the tree so more air gets in? Why is more air needed?
• Do I need an extra burnout furnace for 3D prints?
• Should I rotate the cuvette to have the opening facing upwards?
• What would happen if I rotated the cuvette / rotated it too soon?
• Which plaster / embedding compound should I use?
• Do I need to add boric acid?
• Which burnout curve should I use?
• Why does the number of cuvettes matter?

When burning out wax-containing resins, expansion forces can arise if the burnout curve rises too quickly and the 3D prints do not have sufficient time to burn. These expansion forces exert pressure on the sharp edges which then break. We therefore recommend lightly breaking and rounding off the edges beforehand in the CAD software. Do this on both positive and negative edges. This means that, if necessary, the pressure will be better distributed and the sharp edges will not break in the plaster. You should also ensure that the height or depth of the lettering is kept as low as possible to avoid breaking.

When burning out wax-containing resins, expansion forces can arise if the burnout curve rises too quickly and the 3D prints do not have sufficient time to burn. These expansion forces exert pressure on the sharp edges which then break. We therefore recommend lightly breaking and rounding off the edges beforehand in the CAD software. Do this on both positive and negative edges. This means that, if necessary, the pressure will be better distributed and the sharp edges will not break in the plaster. You should also ensure that the height or depth of the lettering is kept as low as possible to avoid breaking.

We recommend that you attend one of our 3D printing training sessions. These training sessions cover a variety of different geometries and their properties.
For more information, please contact info@hafner-3d.com

Both Stl and Obj files can be imported. We have developed our own data format (H3D) that can read by our 3D printers. These files are generated by our Hafner 3D software.

CAD software is like a toolbox filled with a wide variety of different tools. Each of these tools has its specific purpose and you must first learn how to use them correctly. It is practically a craft in its own right.
You therefore need to find out which of the functions (tools) you need.
It is important to think about which geometries and designs you might want to learn e.g. during the first year and what your personal goals are. This will help you reduce the number of software packages you might wish to consider using.
Most CAD programs also provide various plugins that extend the features of the software. To get more insight into 3D printing, we recommend that you attend one of our 3D printing training sessions. These training sessions cover a variety of different geometries and their properties.

For more information, please contact info@hafner-3d.com