Patent ID: 11969805
Assignee: SOOCHOW UNIVERSITY
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 1:
2. The method for milling a large-diameter aspheric surface by using a splicing method according to claim 1, wherein an equation of the generatrix equation f1 of the aspheric surface is: z2=2*R0*x−(1+k)*x2, wherein R0 is a curvature radius of a vertex of the aspheric surface, the nth ring has a curvature radius of Rn=sqrt(R02−k*xn2), k is a quadratic conic coefficient, x is a horizontal coordinate independent variable, and z is a vertical coordinate corresponding to the x coordinate; steps for machining the aspheric surface are as follows:
(1) machining an aspheric lens body based on the curvature radius of R0 of the vertex and the diameter of D of the aspheric surface, and machining an original spherical surface with a radius of R0 and a diameter of D from the aspheric lens body material;
(2) fixing the aspheric lens body in step (1) on a turntable of the numerical control machine tool, and making an optical axis of the aspheric lens body coincide with a rotation axis of the turntable of the numerical control machine tool; wherein the numerical control machine tool has at least two translation motion axes: an X-axis and a Z-axis, and two rotation axes: a B-axis and a C-axis, wherein the B-axis is a rotation axis around a Y-axis, the C-axis is a rotation axis around the Z-axis, and a rotation axis of the turntable of the numerical control machine tool is located at the C-axis; and a spindle of the numerical control machine tool is located at the Z-axis;
(3) installing an annular tool on the spindle of the numerical control machine tool, wherein the annular tool has an outer diameter of TD, and a convex round chamfer between the outer diameter and an inner diameter of the annular tool has a radius of r0; and TD<D/4; and establishing an origin of a workpiece coordinate system at a vertex of the original spherical surface;
(4) solving the width dx of any ring based on the Nth ring, the (N−1)th ring, the positioning accuracy, and the generatrix equation of the aspheric surface; and
(5) using the annular tool on the numerical control machine tool to sequentially machine the first ring to the Nth ring, wherein when the nth ring is machined,
the C-axis rotates continuously and uniformly,

xn=n*dx; 

BB=a sin((TD−2*r0)/(2*(Rn−r0)));

a B-axis coordinate is: B=a sin(xn/Rn)+BB;
an X-axis coordinate of the tool center in the workpiece coordinate system is:

XT=xn+(((TD−2*r0)+2*r0*sin(BB))/2)*cos(B); and

a Z-axis coordinate is:
when k=−1:

ZT=(((TD−2*r0)+2*r0*sin(BB))/2)*sin(B)+(R0−sqrt(R02−(1+k)*xn2))/(1+k), or

when k=−1:

ZT=(((TD−2*r0)+2*r0*sin(BB))/2)*sin(B)+xn2/(2*R0);

wherein * is the multiplication operator, sqrt is the square root calculation operator, and sin, cos and a sin are the sine, cosine and arc sine operators respectively.