JPH0669725B2 - 3D shape formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention provides a three-dimensional shape for displaying three-dimensional three-dimensional information to a resin material container every time a liquid photocurable resin material is sequentially layered. In the method of forming a laminated shape by performing exposure scanning by beam irradiation by a laser beam optical system to selectively form a layer, a layer thickness of each layer made of a liquid photocurable resin material for performing the exposure scanning is set to By making it equal to the reciprocal of the light absorption coefficient of the material, and by effectively utilizing the exposure energy of the irradiation beam per volume, the total exposure and curing time required to form a three-dimensional shape can be shortened to the minimum. The three-dimensional shape can be efficiently formed in a short time.

[Industrial application field]

The present invention relates to a method for forming a three-dimensional shape for displaying three-dimensional three-dimensional information by repeating a step of forming a cured resin layer by supplying a liquid photo-curable resin material and selectively exposing a laser beam to a laser beam for exposure. In particular, the present invention relates to an improvement in an exposure and curing method that shortens the total exposure and curing time required to form a three-dimensional shape.

As a method of displaying three-dimensional stereoscopic information, a perspective view display, a projection view display, a contour line display, a stereoscopic display by Holographic and the like are widely used. These methods are all 3 except for the stereoscopic display by Holocalyphy.
Includes a procedure for converting dimensional information into two-dimensional information,
This is not always a satisfactory method for intuitively grasping and fully understanding the displayed three-dimensional shape.

In this respect, although the stereoscopic display by the holography is visually and intuitively advantageous over the above-mentioned display methods,
However, it requires a reproducing apparatus, and it is not easy to form and display a non-existent three-dimensional virtual object or a three-dimensional bird's-eye view.

Therefore, as a method of relatively easily forming a stereoscopic model that intuitively grasps and displays stereoscopic information in recent years, for example, using a photocurable resin material and a laser beam scanning optical system, A method has been proposed in which a step of selectively exposing and curing a photo-curable resin material layer based on three-dimensional information is repeatedly repeated to stack cured layers to form a three-dimensional model having a complicated stacked formation.

In such a three-dimensional shape forming method, there is a method capable of shortening the total exposure and curing time required for forming a three-dimensional shape by setting efficient exposure and curing conditions according to the photocuring characteristics of the photocurable resin material used. Is required.

[Conventional technology]

Conventionally, in order to form a three-dimensional model shape for displaying three-dimensional three-dimensional information by using a laser beam irradiation means using a photo-curing resin material, first, as shown in FIG. The liquid photocurable resin material 5 for the first layer corresponding to the thickness obtained by dividing the three-dimensional model shape to be created into several circular slices is supplied into the resin material container 1 placed on ,
After the surface of the supplied resin material 5 is flattened, the resin material 5 is
The sub-scanning base 2 is finely adjusted in the vertical direction so that the surface becomes the focus level of the laser beam 4 for exposure and irradiation.

Next, as shown in FIG. 3 (b), based on the three-dimensional pattern data obtained by dividing the surface of the resin material 5 into several circular slices, the laser beam reflected by the scanning reflecting mirror from the laser beam optical system. 4, or the sub-scanning table 2 is moved and scanned in the X and Y directions to irradiate the laser beam 4 to form the first cured resin layer 5a selectively exposed and cured.

Next, as shown in FIG. 3C, the liquid photocurable resin material 6 for the second layer is supplied, and after the surface is flattened, the surface of the resin material 6 is exposed to the laser beam 4 for exposure and irradiation. The sub-scanning base 2 is again finely adjusted in the vertical direction so as to reach the focus level, and then, as shown in FIG.
Based on the three-dimensional pattern data, the surface is similarly irradiated with the laser beam 4 to form the second cured resin layer 6a selectively exposed and cured.

After repeating the same steps, the third layer of the liquid photo-curable resin material 7 as shown in FIG. 3 (e) is selectively exposed and cured to form the third cured resin layer 7a. , Finally taking out the three-dimensional cured resin image formed in a laminate from the unexposed liquid photocurable resin material, by washing away the liquid photocurable resin material adhered with a cleaning treatment solution or the like, As shown in FIG. 3 (f), a three-dimensional model shape 8 for displaying desired three-dimensional three-dimensional information is created.

[Problems to be solved by the invention]

By the way, when a three-dimensional shape having a total thickness (total height) of H is formed by a conventional three-dimensional shape forming method, the layer thickness of each resin layer to be photocured is x, and the one resin layer is irradiated with a beam. T is the exposure time required for exposure curing, the number of photo-curable layers required for forming a three-dimensional shape having a total thickness H is n, and the total exposure curing time required for forming a three-dimensional shape having a total thickness H is Let T be the relationship shown in the following equation between them.

n · x = H ··· (1) n · t = T ··· (2) That is, for forming a three-dimensional shape having a total thickness (total height) of H, each is photocured. Layer thickness of one resin layer x
If the thickness is increased, the exposure time t required for the photo-curing of one layer is increased, but the total number n of layers is decreased, and conversely, if the layer thickness x is decreased, the exposure time t required for the photo-curing is decreased. , It is necessary to increase the total number of layers n.

However, in the conventional formation of a three-dimensional shape, by effectively utilizing the curing characteristics of the photocurable resin material used for the formation,
Since no consideration was given to shortening the total exposure curing time T required for forming, the total exposure curing time T
There was a problem of spending a long time on.

In view of the above conventional circumstances, the present invention can shorten the total exposure curing time T required for formation to the minimum by the exposure curing conditions that maximize the curing characteristics of the photocurable resin material used for forming a three-dimensional shape. It is an object of the present invention to provide a method for forming a three-dimensional shape.

[Means for solving problems]

In order to achieve the above object, the present invention selectively performs exposure scanning by beam irradiation by a laser beam optical system to the photocurable resin material every time the liquid photocurable resin material is sequentially supplied in layers to the resin material container. When a three-dimensional shape composed of a laminated cured resin image is formed by photo-curing the liquid photo-curable resin material, the layer thickness of each layer is made of the liquid photo-curable resin material that is exposed and scanned by the beam irradiation. And the reciprocal of the light absorption coefficient of (3) to minimize the exposure energy per volume.

That is, the light absorption coefficient of the photocurable resin material with respect to the irradiation beam is α, the exposure energy per unit area where the photocuring of the resin material starts, the so-called threshold exposure energy is Eth, the exposure energy per unit area is E, and the When the layer thickness of one photocurable resin layer is x and e is the base of natural logarithm, the following relational expression holds.

Eth = Ee ^{− α} x (3) Therefore, as the exposure-curing condition of the present invention, the fact that the photo-curing property of the photo-curing resin material is given by the formula (3) is used to obtain a three-dimensional shape. The total exposure curing time T for forming the film is shortened to the minimum.

[Action]

In the method for forming a three-dimensional shape of the present invention, when the irradiation beam power is P and the total area of one scanning region of the photocurable resin material is S, the exposure energy E per unit area and one layer are required for photocuring. There is a relation of the following equation with the time t.

E = P · t / S (4) By substituting this into the equation (3) and using the equations (1) and (2), the total exposure time T required to form a three-dimensional shape The relationship between the layer thickness x and the layer thickness x of one resin layer to be exposed to curing is calculated as follows: T = (SH · Eth / P) · (e ^α x / x) ··· (5) (5) Thus, the total exposure time T is P, S,
When H and Eth are constant, x = 1 / α and the minimum value S ・ H ・ Eth
・ Take α / P.

In order to set the layer thickness x of the single photo-curable resin layer to x = 1 / α, from the formulas (3) and (4), P · t / S = e · Eth (6) The exposure and curing conditions are set as follows.

Further, when the above equation (5) is converted into the following equation, P · T / (S · H) = Eth · e ^α x / x (7) The left side is per unit area required to form a three-dimensional shape. The exposure energy, that is, the volume exposure energy density. When the total exposure curing time T is shortened to the minimum, the right side of the equation (7) is also minimized, and the exposure energy of the irradiation beam is most effectively used.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

In this example, the relationship between the exposure energy E per unit area and the resin cured thickness x was measured for five types of liquid ultraviolet curable resin materials used to form a three-dimensional shape, and the result is shown in FIG. As described above, in any of the samples, there is a linear relationship between the resin cured thickness x and the logarithm of the exposure energy E per unit area, and the equation (3) of Eth = Ee ^{− α} x is established.

The sample composed of the above-mentioned five kinds of ultraviolet curable resin materials is, for example, CV-7016 manufactured by Matsushita Electric Works, which contains an epoxy acrylate resin and an acrylate monomer as main components.
-3 (Sample 1), CV-7307-6 (Sample 2), CV-7809-4 (Sample 3), and PI-170 (Sample 4), a Teijin product whose main component is not revealed by the manufacturer's Knowhow. ) And FP-70 (Sample 5), a product of Asahi Kasei containing unsaturated polyurethane resin as the main component.

Then, from FIG. 1, the light absorption coefficient α and the exposure energy per unit area where the photo-curing of the resin material starts, that is, the so-called threshold exposure energy Eth, are obtained from the above-mentioned five kinds of samples, and the results are shown in a separate table.

Furthermore, the relationship between the volume exposure energy density of the irradiation beam and the layer thickness of one resin layer to be photocured for each sample is obtained from each of these values and the equation (7), and the relationship is shown in FIG.

Therefore, in the method for forming a three-dimensional shape of the present invention, as in the conventional case, every time the liquid ultraviolet light curable resin material is sequentially supplied in layers to the resin material container, the resin material is exposed by beam irradiation by the laser beam optical system. When a three-dimensional shape composed of laminated cured resin images is formed by scanning and selectively photocuring, the layer thickness of each layer of the ultraviolet curable resin material used for the formation is set to the predetermined resin shown in FIG. The minimum thickness from the relation curve of the material, that is, the optimum layer thickness 1 / α equal to the reciprocal of the light absorption coefficient of the ultraviolet curable resin material is adopted as shown in the attached table, and the irradiation beam Based on the power P and the total area S of the scanning region of one layer of the resin material, the time for exposing and curing one layer of the resin material is a t value determined by P · t / S = e · Eth in the equation (6). If exposure curing is performed at the scanning speed of Is used most efficiently, the total exposure curing time T required to form a three-dimensional shape in a laminated form is shortened to the minimum, and the formation of the three-dimensional shape is shortened.

〔The invention's effect〕

As is clear from the above description, according to the method for forming a three-dimensional shape according to the present invention, the thickness of each layer of the photo-curable resin material for forming a three-dimensional shape composed of a cured resin image in a laminate, Set the value equal to the reciprocal of the light absorption coefficient of the resin material and minimize the exposure energy of the irradiation beam to use the most efficient exposure and curing conditions to minimize the total exposure and curing time required to form a three-dimensional shape. It has an excellent advantage that a desired three-dimensional shape can be efficiently formed in a short time.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of photo-curing thickness characteristics of various photo-curable resin materials used in the method for forming a three-dimensional shape of the present invention, and FIG. 2 is various photo-curable resins used in the method for forming a three-dimensional shape of the present invention. FIG. 3 is a diagram showing an example of the volumetric energy density of a material, and FIG. 3 is a cross-sectional view of essential parts showing a conventional method for forming a three-dimensional shape in the order of steps.

Claims (1)

[Claims] 1. Whenever a liquid photocurable resin material is successively supplied in layers to a resin material container, the resin material is exposed to light by beam irradiation by a laser beam optical system to selectively perform photocuring, and laminated. In the method for forming a three-dimensional shape including a cured resin image, the layer thickness of each layer of the liquid photocurable resin material that is exposed and scanned by the beam irradiation is equal to the reciprocal of the light absorption coefficient of the resin material. In addition, the method for forming a three-dimensional shape is characterized in that the exposure energy per volume is minimized to shorten the total exposure curing time.