Why can't the model stick to the platform in UV curing printing?
In UV curing printing, it is easy to detect and frustrating that the model does not adhere to the platform: it not only delays time, but also increases equipment wear and tear, which will also bring troublesome processing work.
Why can't the model stick to the platform?
There are three possible factors:
① Underexposure at the bottom
When pulling out the mold, the model will generate tension on both sides, adhesion of the release film, and adhesion of the platform. Due to the hardening and expansion of the resin during overexposure, it will tightly fill every surface of the platform. Therefore, the actual adhesion surface of the platform is larger than that of the release film. In addition, the release film has a coating, which causes the release film to detach first during drawing. When the exposure is insufficient, it will reduce the adhesion area and bonding effect of the platform, causing the model to detach from the platform;
② The platform surface is too smooth
From factor ①, we know that the rougher the platform surface, the stronger the adhesion effect. A platform that is too smooth cannot firmly grasp the model to resist the pulling force below during the drawing process;
③ Platform not leveled properly
If the platform is not leveled or not leveled properly, and one side or corner of the platform is high, it will cause the model to not stick on this side. At the same time, due to lateral pulling, it will not stick when printing. The Aurora Erwo G5 platform uses this principle to pull the mold from the release film side to side. The manifestation of factor ① is that there is a probability of detachment from the platform at any time during printing, and under this factor, as the exposure and leveling of the printing continue, if the initial layer adhesion is successful, there will be a thicker bottom in the upward direction or further partial detachment;
④ Insufficient flatness of the platform
Due to processing technology issues, most metal surfaces without treatment will have a concave center, and slight deformation has little effect on model printing. However, when the relative concave is greater than 1mm, it is easy for the model to fall off, especially when the printing layer height is larger, the probability of occurrence is higher: when printing with a large layer height, the bottom layer in the middle will be exposed as thick, The inability of light to penetrate results in the resin on the platform surface not being cured or not fully cured. The performance during printing is the same as factor ③. As the printing becomes more firm, the difference is that this factor will make the model in the middle of the platform more prone to detachment;
⑤ Material characteristics
Resin materials can also affect the adhesion of the model. Special resins contain many additives, which can affect the curing effect. It is more difficult to adhere under the same exposure time, and a small portion of the resin itself has a strong or weak photosensitizer "absorption" ability, which can also affect the curing effect.
Doing four tasks well can increase the success rate of adhesion to 90%
① Grinding platform
Don't cherish your machine. Use low grit sandpaper or a hard object to rub the printing platform vigorously, and the more flowers, the better the adhesion effect. The mesh platform of the goofoo Lens-m model, for example, provides strong adhesion through the holes, even for full flat tabletop printing. The bottom layer only needs a maximum exposure of 20 seconds to successfully adhere. Of course, for those who pursue individuality, you can even carve a "tattoo" on the platform, and if conditions permit, you can polish the model to a higher level before rubbing it, resulting in better results.
② Increase exposure time
If you have just obtained a 3D printer or changed to a new resin, it is recommended to use an exposure testing model to detect the optimal exposure time for the bottom layer. Of course, you can also use a longer exposure time for the bottom layer, and after success, continuously reduce the exposure time for debugging;
③ Connect the bottom valve together
In the slice setting support, the model can generate a bottom valve, which can increase the initial contact surface. By default, the bottom valve will have a larger projected area than the model. Therefore, in multiple model slices, we can move the model horizontally to connect the bottom valves of the model into one piece. This can effectively solve the risk of failure caused by the platform not being leveled or concave, and also avoid the occurrence of single mold detachment;
④ Choose materials that are easy to print
Generally, functional resins increase the difficulty of printing. Carefully consider your actual needs, and if not necessary, you can choose ordinary rigid resins and related color mixing resins that are easier to print.
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