How to draw mold assembly drawings

The main purpose of mold assembly drawings is to reflect the basic structure of the mold and express the mutual assembly relationships between parts, including positional relationships and matching relationships. . Starting from this purpose, the most basic requirements that a mold assembly drawing must meet are:

First of all, each part (or component) in the mold assembly drawing cannot be omitted. No matter which mold part, all parts in the assembly drawing are It should be expressed;

Secondly, the position of each part in the mold assembly drawing and the assembly relationship with other parts should be clear. In the mold assembly drawing, in addition to sufficient projection drawings to illustrate the mold structure, necessary cross-sectional views, cross-sectional views, technical requirements, title blocks and detailed columns for filling in each part, there should also be other special expression requirements.

The drawing requirements for mold assembly drawings must comply with national drawing standards, which are summarized as follows:

⑴ The layout and proportion of the general assembly drawing.

① The relevant regulations on drawing format and format in the national standard mechanical drawings (GB/T14689-2008) should be followed.

② Drawings can be drawn according to customary or specially specified drawing methods in mold design.

③ Try to draw at a ratio of 1:1, and if necessary, scale according to the ratio required by mechanical drawings, but the dimensions are marked according to the actual dimensions.

④ The layout method of the mold assembly drawing is shown in Figure 1-72.

(a) Layout of the general assembly drawing of the stamping mold (b) Layout of the general assembly drawing of the plastic mold

Figure 1-72 Layout method of the general assembly drawing of the mold

⑵ Mold design drawing sequence

① Main view. When drawing the general assembly drawing, a stepped section or a rotated section should be used to try to make each type of mold parts reflected in the main view. Draw from inside to outside, from top to bottom, that is, according to the order of product parts drawing, punch mold, and concave mold. When there are too many parts, only half of them are allowed to be drawn. When it is impossible to draw them all, they can be drawn in the left view or top view. .

② Top view. "Open" the upper (fixed) mold of the mold along the stamping or injection direction, look at the "opened" upper (fixed) mold or lower (movable) mold from top to bottom along the stamping or injection direction, and draw a top view. The main and overhead views should be drawn in one-to-one correspondence.

③ Left and right views. When the main and top views do not clearly express the assembly relationship, or when the plastic mold is in the horizontal working position, draw the left and right views to "open" the fixed mold in the injection direction to see the structure of the movable mold part.

⑶ Requirements for the main view of the mold assembly drawing.

① Before drawing the main view, you should first estimate the approximate length and width of the entire main view, and then choose an appropriate proportion for drawing. After the main view is drawn, there should generally be a 50-60mm gap between it and other views or outer frame lines.

② All parts of the mold should be drawn as much as possible on the main view, which can be a full section view, a half section view or a partial view. If there is something that cannot be expressed clearly, you can add other views.

③ When cutting into solid rotating body parts such as circular punches, guide posts, top blocks, bolts (screws) and pins in the cross-sectional view, no hatching lines are drawn on the cross-section; sometimes for the sake of drawing structure Clear, non-rotating punches do not need to be hatched.

④ The drawn mold should generally be in a closed state, as shown in Figure 1-75, or close to a closed state, or half of it can be in a closed working state and the other half in an unclosed state.

⑤ Only one contour line should be drawn for the contact surface or mating surface of two adjacent parts; the non-contact surface or non-mating surface (different basic sizes) of two adjacent parts should be drawn regardless of the size of the gap. Draw two outline lines to indicate the presence of gaps. When adjacent parts are cut, the inclined direction of the section lines should be opposite; when several adjacent parts are cut, the section lines can be distinguished by different spacing (density), inclined direction, or staggering. However, the section line directions and intervals of the same part in different views on the same drawing should be the same.

⑥ Part of the process structure of the parts on the die assembly drawing, such as chamfers, fillets, undercuts, pits, bosses, knurling, engraved lines and other details do not need to be drawn. Line segments resulting from chamfering such as bolts, nuts, pins, etc. are allowed to be omitted. For the connection of the same component group, such as bolts, screws, and pins, it is allowed to draw only one or a few places, and the rest can be represented by dotted lines to indicate the center position.

⑦ When the cross-section thickness of the parts on the mold assembly drawing is less than 2 mm, blackening is allowed to replace the section line, such as gaskets, stamped sheet metal parts and blanks in the mold.

⑧ How to draw the spring on the assembly drawing. It is not necessary to draw the structure blocked by the spring. Only the center of the spring wire section or the outline of the outer diameter of the spring can be drawn for the visible part of the outline, as shown in Figure 1-73(a). Sections with a spring diameter less than or equal to 2 mm can be painted black or drawn schematically, as shown in Figure 1-73 (b) and (c).

Figure 1-73 The prescribed drawing method of the spiral compression spring in the mold assembly drawing

The spring can also be drawn in a simplified way, that is, a double-dot dash line represents the outline, with a cross in the middle It is represented by a double-dotted line, as shown in Figure 1-74.

⑷ Requirements for the top view of the mold assembly drawing

The top view generally only draws the lower (moving) mold. For molds with symmetrical structures, the upper (fixed) and lower (moving) molds can also be drawn. Draw half of each, drawing one side view or other views if needed.

When drawing a top view of the mold structure, the structural shape after the upper mold part is removed should be drawn. The focus is to reflect the working parts installed in the lower mold part. There should also be a 50-60mm gap between the top view and the frame, main view, title bar or details bar.

Figure 1-74 Simplified drawing method of spring

⑸ How to draw the serial number lead line.

Before drawing the serial number lead-out line, you should first count the number of parts in the mold and then make overall arrangements

Task 1 Blanking progressive die

Fig. 1-75 Compression spring punching and blanking progressive die assembly diagram

Arrangement. The serial numbers should generally be compiled in order of clockwise rotation with the main view as the center. Generally, the serial numbers are not marked on the left side, leaving space for marking the closing height and tolerance. In the mold assembly diagram shown in Figure 1-75, before drawing the serial number lead-out line, it is counted that there are 27 parts in the entire mold. Therefore, the designer considers arranging 9 serial numbers on the top, 9 serial numbers on the right, and 9 serial numbers on the bottom. 9 serial numbers. According to the above arrangement, then draw 27 short horizontal lines with equal spacing, and finally draw the serial number lead-out line from the part to the short horizontal lines from the mold.

Follow the drawing steps of "Count the number of parts → Arrange the position of the serial number → Draw a short horizontal line → Draw the serial number lead-out line", so that all the serial number lead-out lines can be arranged neatly and with equal spacing, avoiding the difficulty of beginners in drawing The phenomenon of "overlapping and crossing" often occurs in serial number lead lines.

Of course, if you want to draw the serial number in the top view (Figure 1-75), you can also draw the lead lines clockwise and mark the serial number. The annotation regulations are as follows:

① The font size of the serial number should be one or two sizes larger than the dimensions on the drawing. Generally, a thin solid line is used to draw a guide line from within the outline of the injected part. A dot is drawn on one end of the part and a horizontal thin solid line is drawn on the other end.

② Write the serial number directly on the horizontal thin solid line.

③ When drawing guide lines, do not cross each other or be parallel to the section line.

⑹ Selection of section. As shown in Figure 1-75, the selection of the upper mold section of the mold should focus on the fixation of the punch, the shape of the female mold opening, the assembly relationship between the templates (i.e. the installation of screws and pins), the mold handle and The installation relationship between the upper mold bases and the assembly relationship of the punching system consisting of the driving rod, the driving plate, the ejector rod and the push block, etc. The above-mentioned areas that need to be highlighted should be fully sectioned or half-sectioned as much as possible, and some other assembly relationships can be drawn without sectioning and drawn with dotted lines or omitted and not drawn in other views (such as top views). Just express.

The selection of the cross section of the lower part of the mold should focus on reflecting the installation relationship of the convex and concave molds, the shape of the holes of the convex and concave molds, the installation relationship between the templates (i.e. how to install screws and pins), the shape of the leakage hole, etc. , these parts should be fully sectioned as much as possible, and other non-key parts should be simplified as much as possible.

In Figure 1-75, the upper mold part is fully sectioned, showing the fixation of the punch, the shape of the hole of the female mold, the connection between the mold handle and the upper mold base, and the installation of screws and pins (and the pins are arranged on the left (with fastening screws, unloading screws and springs arranged on the right), the assembly situation of the stopper pin is expressed by dotted lines and partial cross-sectional views.

⑺ How to draw screws and pins. When drawing screws and pins, you should pay attention to the following points:

① The dimensions of each part of the screw must be drawn correctly. The approximate drawing method of a screw is: if the diameter of the thread part is D, the diameter of the screw head is drawn as 1.5D, and the countersunk depth of the head of the hexagon socket screw should be D 1~3mm; when both pins and screws are used, the diameter of the pin should be Choose the same diameter as the screw or one size smaller (that is, if you choose M8 screws, the pin should be Ф8mm or Ф6mm).

② When drawing screw connections, be careful not to miss lines. Taking screw 3 in Figure 1-75 as an example, the screw is only threaded with the punch fixing plate 10 at the tail, and the screw should be through holes through the backing plate 9 and the upper mold base 1.

③ When drawing pin connections, be careful not to miss lines. Taking the pin 4 in Figure 1-75 as an example, the through-hole punch fixing plate 10 and the upper mold base 1 need to be positioned with pins, while the backing plate 9 does not need to be positioned with pin 4, so it should be a through hole.

⑻ How to draw workpiece drawings.

① The workpiece drawing is a stamping or plastic part graphic obtained after stamping or molding, as shown in Figure 1-75. It is generally drawn in the upper right corner of the assembly drawing, and the name of the material, Thickness and necessary dimensions; for products that cannot be completed in one process, the process drawing should be shown on the assembly drawing, and the dimensions related to this process should also be marked.

② The proportion of the workpiece drawing is generally consistent with the proportion of the mold drawing, and can be reduced or enlarged under special circumstances. The direction of the workpiece drawing should be consistent with the stamping direction or molding direction (that is, consistent with the position of the workpiece in the mold). If it is inconsistent under special circumstances, an arrow must be used to indicate the stamping or molding direction.

⑼ Layout drawing in stamping die assembly drawing.

① When using strips and strips, a layout drawing should be drawn, usually under the workpiece drawing in the upper right corner of the assembly drawing or between the top view and the details column.

② The layout drawing should include the layout method, the punching process of the parts, the spacing method (the shape and position of the side blade when using the side blade for spacing), material utilization, step distance, and edge overlap , material width and tolerance, the material fiber direction must be considered for parts in the bending and crimping process. Usually, it can be seen from the cutting line of the layout drawing whether it is a single-process mold, a composite mold or a progressive mold.

③ The feeding direction on the layout drawing must be consistent with the feeding direction on the mold structure drawing so that other drawing readers can see it clearly. As shown in Figure 1-75.

⑽ Technical requirements for mold assembly drawings.

In the general assembly drawing, the requirements, precautions and technical requirements for the mold should be briefly noted. Technical requirements include the equipment model used, mold closing height, mold printing marks, assembly requirements, etc. The blanking mold must also indicate the mold gap. Sometimes the pattern code marked in the upper left corner is compiled by the company based on the product model to facilitate the use and management of the pattern.

⑾ The dimensions that should be marked on the mold assembly drawing

include the mold closing height, overall dimensions, characteristic dimensions (positioning dimensions that match the forming equipment), and assembly dimensions (installed on the forming equipment center distance of screw holes), limit size (distance between starting positions of movable parts).

⑿ Title bar and details bar.

① The title bar and detail bar are in the lower right corner of the general assembly drawing. If the drawing is not large enough, you can create another page.

The format of the title bar and details bar is as shown in the lower right corner of Figure 1-75.

② The details column should at least contain serial number, drawing number, part name, code, quantity, material and remarks, etc.

③ When filling in the part name column, the first and last two characters of the name should be aligned, and the middle characters should be inserted evenly, or left-justified.

④ When filling in the drawing number column, the drawing numbers of all parts drawings should be given. The digital serial number should generally be programmed in sequence with the main view screen as the center and the clockwise direction as the serial number. Since mold assembly drawings are generally counted as drawing number 00, the part drawing numbers in the details column should start counting from 01. Parts without parts drawings do not have drawing numbers.

⑤ The remarks column mainly includes specifications, heat treatment, outsourcing or external processing of standard parts. Generally no other content is noted.

⑥ The main contents to be filled in in the title bar include the name of the mold, drawing proportion and signature. The rest of the content can be left blank.

After the mold assembly drawing is completed, the closed height of the mold, the diameter of the leakage hole, the diameter and height of the mold handle, the height of the driving rod, the outer dimensions of the lower mold base, and other technical parameters related to the press must be reviewed. Is the relationship correct? After review, this example was confirmed to meet the parameter requirements of the J23-16F press. ;