Abstract: after the paper smoke came out, the ash and cigarette butts were thrown around the ground, which hindered the health, and the ashtray was also produced. The ashtray was a tool for holding ash and cigarette butts, which was produced in the end of the 19th century. In order to better prevent pollution of the environment, when shaking the ash, the ash is everywhere, not too hygienic, and not ideal. The author designs a new type of ashtray for this problem. The design features of the ashtray are as follows: a metal arc handle is set on both sides of the ashtray. The handle is connected with the wall of both sides of the ashtray by rivets. It is convenient and practical. Although the structure is relatively simple, it needs to be processed step by step. Design is an art, design is essentially beauty, but the most important is its integrity and practicality.

1、 Preface

Ashtray is a common household product. With the improvement of people's living standard, new requirements are put forward for its function and beauty. This paper designs new products for the shortcomings of old ashtray, completes the solid modeling of the products, draws engineering drawings, and reasonably selects processing equipment and clamps, analyzes processing technology, completes NC programming independently, generates NC code, and finally completes the processing of products. There are three main steps:

1. The key to drawing a new type of ashtray sketch and solid is the application of constraints, stretching and Brin operations by using Cimatron Software design tool.

2. The tool path setting is carried out by using Qi operation skill, including contour selection, parameter setting and tool path generation, etc. it is ready for the next step to implement the workpiece.

3. The sample is made by CNC milling machine, including the professional knowledge of process analysis, workpiece clamping and measurement, and the part programming and processing are completed through final inspection.

2、 Innovation objectives

1. The appearance design is novel, subverting the shape of ordinary ashtray in people's heart, and they have a new feeling.

2. Try to reduce the dust and dust scattered.

3. Try to eliminate or reduce the ash and odor caused by the ash.

4. Try to minimize the damage that the remaining ash has caused to our health again.

5. Make our work, life and study environment more ideal.

3、 Design process

Through the function analysis of the product, the style of ashtray is determined, and it is designed by Cimatron Software, including sketch drawing and editing, solid stretching and trimming, drawing generation and annotation.

4、 Description of processing process

In the process of automatic programming, the process decision is the basis for the smooth completion of ashtray processing. The best processing method must be selected according to the shape characteristics of parts, the material of the workpiece, the precision of processing, the surface roughness, etc., reasonably dividing the processing stage, selecting the appropriate cutting tools, determining the optimal cutting amount, determining the reasonable blank size and shape, and confirming the proper cutting tool The reasonable route is determined to meet the processing requirements, reduce processing time and reduce the cost.

1. Main principles of process division

Since ashtray is composed of multiple surfaces and high precision requirements, in order to meet the requirements of design precision of ashtray, the processing sequence arrangement should follow certain principles:

(l) The principle of coarse first and then refined;

(2) Principle of first machining datum;

(3) Principle of first face and then hole;

(4) The principle of "inside first and then outside";

(5) The principle of reducing the number of tool changes.

2. Machining of selected CNC milling machine

CNC milling machine is most suitable for processing parts with the following characteristics:

(1) Many kinds of small batch production parts;

(2) The parts with complex shape and structure;

(3) Parts with high precision requirements;

(4) Parts requiring frequent modification;

(5) The key parts which are expensive and cannot be scrapped;

(6) The parts that need short production cycle are needed;

(7) Large batch and high precision parts.

See Table 1 for the parameters of NC milling machine.

3. Selection of tools

In NC machining, the horizontal bottom vertical milling cutter is commonly used for milling the internal and external contour of the plane parts and milling plane. The experience data of the relevant parameters of the tool are as follows:

(l) It is that the radius RD of milling cutter shall be less than the minimum radius of curvature of the inner contour of the part Rmin, generally rd= (08-09) Rmin;

(2) It is the machining height h < 1 / 4-1 / 6 RD of the parts to ensure the cutter has enough rigidity;

(3) When milling the bottom of the inner groove with a flat end end milling cutter, the radius of the tool bottom edge is re = R-R, i.e. the diameter is d=2re=2 (R-R), and the tool radius is re=0 9i (RR) when programming. For the processing of some three-dimensional and variable angle profiles, ball milling cutter, ring milling cutter, drum milling cutter, conical milling cutter and disk milling cutter are commonly used.

4. Selection of positioning datum

(l) When selecting the coarse base on time, the main requirement is to ensure that there is enough allowance for each processing surface, so that the position between the machined surface and the non processed surface meets the requirements of the drawing, and special attention shall be paid to obtaining the fine base surface as soon as possible;

(2) The surface with the minimum machining allowance is selected as the coarse datum, and the surface with smooth and smooth surface and large machining area is selected as the coarse datum, so that the workpiece can be positioned reliably and clamped conveniently. The rough datum can only be used once in the same dimension direction, because the rough datum itself is the rough surface without machining, and its surface is rough and the precision is low. If repeated use, there will be a large error. The selection of precision datum should ensure the machining accuracy of parts, and the convenience of clamping and simple structure should be considered. The following principles shall be considered for selecting the fine benchmark when processing ashtray:

① Principle of "datum coincidence": in order to meet the position accuracy of the machining surface relative to the design datum, the design datum of the machined surface shall be selected as the positioning datum.

② "Unified benchmark" principle: when a set of fine datum positioning can be more convenient for processing other surfaces, rough and fine datum positioning shall be adopted in most processes as far as possible.

⑧ Principle of "self as benchmark": when the allowance for finishing or finishing process of workpiece is as small and even as possible, the machining surface itself shall be selected as the positioning benchmark.

④ "Mutual reference" principle: in order to obtain uniform machining allowance or high position accuracy, the principle of mutual benchmark repeated processing can be adopted.

5. Precautions during processing

(1) According to the specific size and process table of design drawings, the precision and requirements of parts are considered comprehensively. The dimensions shall be completed according to the sequence.

(2) Technical conditions: uniform size, determine which surface each dimension is on, and arrange a knife to process it as far as possible to ensure that it is processed within a limited time.

(3) The dimension with small tolerance accuracy shall be processed after the machining step with large deformation. During the trial machining, check whether the tool and fixture interfere, so as to avoid the tool milling off the fixture. According to the test tool, the tool shall be tested

As a result, we can modify the tool compensation value, improve the machining accuracy of the parts, and finally make the tool movement track and programming track coincide.

5、 Key technology of NC milling ashtray

Compared with the ordinary milling, NC milling can process complex profile, high precision and stable quality. Every pulse output by the CNC system, the moving amount of moving parts of the machine tool is called pulse equivalent. The pulse equivalent of NC machine tool is generally o.oolmm, and the high precision CNC machine tool can reach o ooolmm, and its motion resolution is far higher than that of ordinary machine tools, so it can process ash cylinder with high precision requirements. The action of NC machine tool is controlled by program and equipped with tool library. The program contains automatic tool changing instruction. Therefore, the operator only needs to unload parts and monitor the operation of the machine tool, thus reducing the labor intensity of the operator, realizing the machining automation and operation simplification. The processing efficiency is greatly improved. NC milling can get high precision and high technical requirements, such as good surface roughness of ashtray

The above problems are basically impossible to implement in the ordinary milling machine, so we choose CNC milling machine to finish the processing of ashtray.

6、 Display of the processing process of ashtray

1. Cimatron Software design tool and programming are selected.

2. The base of ashtray, two handles and overall processing effect diagram, the difficulty of the ashtray is how to process the two handles and how to control the surface roughness.

epilogue

After a round of design and continuous improvement, with the help of Cimatron drawing software and corresponding processing equipment, we can only design relatively simple products, and there are still many minor aspects that still need to be considered. The shortcomings of the products hope to be improved in the future, making them more perfect. In the process of production, we should constantly overcome difficulties and meet difficulties, and complete innovative projects Objective: to make the products more suitable for the market, meet the needs of customers, bring different experiences to customers, whether it can become a successful innovation and the product needs the test of the market. Among them, whether the design of the product is reasonable, whether the principle is accurate, whether the appearance is beautiful and so on are all problems, and these problems must be faced.