CN102615253A - Silica sand molding method based on fiber laser - Google Patents

Abstract

The invention discloses a silica sand molding method based on a fiber laser and belongs to the machining field of laser rapid prototyping. The method includes steps: coating a layer of phenolic resin on the surface of the silica sand; using modeling software to make a part model to be molded; and implementing layered machining to the model. During a machining process, due to focusing permeability of the silica sand, focus of the laser can be converged behind surface powder, the laser is effective not only to molding of the surface powder but to molding of the under powder of certain depth. The silica sand molding method aims to solve the problem that permeation rate of the fiber laser to the silica sand is more than 90%, and molding effect cannot be achieved by directly using laser beam of the silica sand. By coating the silica sand, the silica sand can be molded and problem that the fiber laser cannot be used for silica machining is solved.

Description

A kind of silica sand forming method based on optical fiber laser

Technical field

The present invention relates to a kind of Laser Processing forming method, use silica sand particle straight forming product, belong to the laser fast shaping field based on the silica sand particle.

Background technology

Casting is manufacturing basis.Foundry goods is the important component part of various machines, and in general the weight of foundry goods accounts for 40%～90% of complete machine weight.According to statistics, China or in the world, in whole casting outputs, 60%～70% foundry goods is produced with sand mold.Silica sand is the main matter of casting sand mo(u)ld, and the manufacturing of silica sand sand mo(u)ld mainly was to make by hand through manual work during conventional cast was produced, and productive labor intensity is big, and environment is poor, and is high to workman's specification requirement, and the production cycle is long and sand-mould quality is unstable.

Rapid laser-shaping technique is based on a kind of high-new manufacturing technology of material method of piling, is considered to a great achievement in the field of making over nearly 20 years.Rapid shaping technique is exactly to utilize the data of three-dimensional CAD, through rapidform machine material from level to level is piled into the entity prototype.Under computer control, adopt distinct methods to pile up material based on discrete principle of piling up, finally accomplish the technology of the moulding and the manufacturing of part.Because rapid shaping technique has adopted brand-new growth processing method, has thoroughly broken away from the restriction of traditional removal processing method, only need the man-hour of traditional diamond-making technique 10%～30% and 20%～35% cost just can directly produce product model or sample.It integrates technology such as mechanical engineering, CAD, reverse Engineering Technology, layering manufacturing technology, Numeric Control Technology, material science; Can be automatically, directly, change design philosophy into prototype or direct finished parts quickly and accurately with certain function, thereby a kind of realization means of high efficiency, low cost are provided for the aspects such as verification of the manufacturing of part prototype, new design philosophy.In recent years, along with the development of rapid laser-shaping technique, it was with the obvious advantage complex model moulding manufacture view, rapid shaping technique was used with the sand mold making have very big potentiality.But mostly used laser instrument is optical fiber laser in the rapid shaping, and silica sand basically all sees through it, can't absorb, thereby can't carry out machine-shaping.This is the main bottleneck that laser fast shaping is applied to sand mold molding

The innovation part of this method is, uses optical fiber laser directly to process its transmitance up to 90% above silica sand material.Make the making of silica sand sand mo(u)ld to reduce labour intensity greatly and to make molding time through the method moulding quickly and accurately of rapid shaping.

Summary of the invention

The present invention is intended to solve the problem that optical fiber laser can't carry out processing and forming to silica sand.The precinct laser sintering equipment that the present invention adopts comprises computer, optical fiber laser, motion control card, forming room, shop powder feeding mechanism, and material comprises and is coated with silica sand, phenolic resins.

Moulding for sand mo(u)ld comprises the steps:

(1) silica sand mixes with phenolic resins according to a certain percentage.Specific operation process is heated in the puddle mixer between 200～220 ℃ for earlier silica sand being added, and presses phenolic resins and silica sand weight ratio 1.9%～2.1% adding phenolic resins then.When sand temperature drop to 105～110 ℃; This moment, phenolic resins basically evenly was coated on the silica sand surface; Add the methenamine aqueous solution (methenamine: quality is than=1: 1～1.5) make phenolic resin curing, its addition account for the phenolic resins quality 10%～15% between.In mixed system process, need to feed compressed air, quicken the dispersion process of cooling and sand grains.

(2) product model that will moulding imports in the machining software, and according to the shape of model to be processed, the precision that reach and the size of particle are carried out layering and filled and handle;

(3) calculate the total amount of required powder particle according to the size of model, the hybrid particles of capacity is added in the powder feeding mechanism, guarantee that powder particle is sufficient in the process;

(4) open laser instrument, adjustment laser power, process velocity and sweep spacing are carried out layering machine-shaping to product.

We's ratio juris is: through coat one deck phenolic resins on the silica sand top layer; Laser beam is carrying out processing and forming according to the product shape to particle, at the process mesexine particle of laser beam flying since phenolic resins to the absorption of laser, phenolic resins fusing; Can adhere to together; Particle at certain depth below the top layer throws under the effect of the laser beam that advances, and phenolic resins also produces melting phenomenon, thereby the silica sand particle of levels is adhered to together more closely.

The problem that the present invention mainly solves be optical fiber laser to the transmitance of silica sand very up to more than 90%, directly light beam is acted on the silica sand particle and can't reach the machine-shaping effect.Through silica sand is coated processing, thereby make that silica sand can machine-shaping, solved the difficult problem that optical fiber laser can't be processed silica sand.

The specific embodiment

At first be necessary to be pointed out that at this present embodiment only is used for the present invention is further specified, can not be interpreted as restriction protection domain of the present invention.

Instance of the present invention selects for use the small-power optical fiber laser as the moulding thermal source, and scanning system adopts the digital scanning galvanometer; The silica sand grain diameter is 100 μ m, and the surface is coated with 1 μ m phenolic resins.Use the Pro/E 3 d modeling software to create external diameter and be 30mm, internal diameter is that hollow hemisphere and the bottom of 25mm is 30mm * 30mm, and the top is diameter 30mm, highly is the model of 30mm.This instance is undertaken by following method: adopt hot cladding process, obtain the required coated sand of processing and forming with mixing to coat in silica sand and the phenolic resins adding puddle mixer.Handle carrying out hierarchy slicing in the threedimensional model importing control software that needs moulding, setting machined parameters is power 5W, sweep speed 70mm/s, sweep spacing 0.1mm.According to hierarchical information, model is carried out processing and forming successively until the moulding of accomplishing all synusia.

Claims (1)

1. based on the silica sand processing molding method of optical fiber laser, it is characterized in that, comprise the steps:

(1) is heated in the puddle mixer between 200～220 ℃ first silica sand is added, presses phenolic resins and silica sand weight ratio 1.9%～2.1% adding phenolic resins then; When sand temperature drop to 105～110 ℃, add the methenamine aqueous solution and make phenolic resin curing, methenamine in the methenamine aqueous solution: quality is than=1: 1～1.5, in the methenamine aqueous solution addition be the phenolic resins quality 10%～15% between; In mixing the system process, need to feed the compressed air of the dispersion process of quickening cooling and sand grains;

(2) product model that will moulding imports in the machining software, and according to the shape of model to be processed, the precision that reach and the size of particle are carried out layering and filled and handle;

(3) calculate the total amount of required powder particle according to the size of model, the hybrid particles of capacity is added in the powder feeding mechanism, guarantee that powder particle is sufficient in the process;

(4) open laser instrument, adjustment laser power, process velocity and sweep spacing are carried out layering machine-shaping to product.