Resin liquid-level control for photo-solidification quick formation and resin coating method and apparatus

Abstract

The invention relates to a method and device for controlling the liquid level of a photosensitive resin and coating a resin layer for photocuring rapid prototyping. The computer-controlled micropump injects the resin in the auxiliary tank into the scraper with a cavity through a flexible pipe, and simultaneously completes the control of the liquid level of the resin and the coating of the resin layer on the surface of the workpiece through the horizontal movement of the scraper on the liquid surface of the main tank. The present invention can not only overcome the disadvantages that the ordinary blade-type scraping method is easy to damage the workpiece and the coating is uneven, but also can overcome the negative pressure adsorption scraper that is easy to lose negative pressure and reduce the uniformity and layer thickness accuracy of the resin coating. shortcoming. At the same time, since the uncured resin coating layer is formed on the surface of the workpiece, it only needs to move the bracket down by a distance of a solidified layer thickness, so it has little influence on the fluctuation of the resin liquid level in the main tank and does not require a long wait. Leveling time thus improving work efficiency.

Description

technical field [0001] The invention belongs to the technical field of rapid prototyping, and mainly relates to the control of the liquid level of photosensitive resin in the light-curing rapid prototyping process and the resin layer coating on the surface of workpieces to be formed. Background technique [0002] Rapid prototyping technology is also referred to as rapid prototyping technology. Its core is a new digital-based forming technology. It can automatically, quickly, directly and accurately transform design ideas into prototypes with certain functions or directly manufacture parts (workpieces). It is a powerful tool to improve product quality and reduce product cost by shortening the product development cycle as much as possible. Photocuring rapid prototyping is based on the photosensitive resin that can be cured quickly under the light radiation of a specific wavelength. According to the CAD three-dimensional model data of the workpiece, the surface layer of the pho...

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Problems solved by technology

The former needs to adjust the position of the knife edge to be exactly the same as the height of the resin liquid level during work, and use the edge of the knife edge to scrape off the excess resin and accelerate the leveling of the resin. Because there is a pressure difference between the front and back of the scraper and resin stickiness during the scraping movement. The dragging effect of the stagnation force will cause the backflow of the resin, which will affect the uniformity and layer thickness accuracy of the resin coating layer. In addition, the slight warping of the workpiece caused by the shrinkage of the resin during curing, the error of the control of the resin liquid level and the loading of the workpiece The error in the movement of the worktable will easily make the scraper touch the cured resin layer during movement and destroy the workpiece; the latter is to make the scraper with a cavity structure and adjust the position of the knife edge to be slightly higher than the resin liquid level. (0.1mm~0.3mm), using the principle of negative pressure and the capillary phenomenon of tension on the surface of the resin, a certain amount of resin can be stored in the cavity of the scraper. When the scraper moves, the edge of the scraper can scrape the protruding part of the uncured resin layer on the workpiece The resin in the scraper cavity can fill up the concave part. Although the scraper with this structure will not directly contact the cured resin layer during movement, there is a gap between the knife edge and the resin liquid surface. Slight changes in the resin liquid level caused by lifting and lowering. When the workpiece sinks, the sag caused by the stickiness of the resin or the rapid movement of the scraper will easily cause the negative pressure in the scraper cavity to affect the coating of the uncured resin layer on the workpiece. The uniformity of the workpiece will eventually affect the quality of the workpiece and even lead to failure

At the same time, the bracket must move up and down when the uncured resin coating layer is formed on the surface of the workpiece in the above-mentioned process, which causes the resin liquid level of the main tank to change greatly, and it takes a long time to wait for the resin to level naturally. Prolong the production time of the workpiece and reduce the work efficiency

[0006] In addition, the above methods of resin liquid level measurement and control and resin layer coating are often independent subsystems in actual use, and the coordinated control between the two subsystems of resin liquid level measurement and control and resin layer coating is relatively complicated.

Therefore, the existing methods are difficult to conveniently realize the precise control of the resin liquid level and ensure the uniformity and layer thickness accuracy of the resin coating layer.

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