The design process of UG mold design structure!

Determination of the motherboard program

In mobile phone design companies, it is usually divided into marketing department (hereinafter referred to as MKT), appearance design department (hereinafter referred to as ID), and structural design department (hereinafter referred to as MD). A mobile phone project starts with a motherboard specified by the customer. The customer chooses the appropriate motherboard according to the market demand. Where can I get the 3D drawing of the motherboard from the solution company, and then find a design company to design a certain style of appearance and structure.

Production of design guidelines

After getting the 3D drawing of the motherboard, the ID cannot be called directly, and MD needs to convert the 3D drawing of the motherboard into six views, and calculate the basic size of the whole machine. This is the basic skill of MD, and I used it as a company recruiting interview. If you have done the mobile phone test independently, you will know if the answer is wrong, even if the resume is rich in experience, it is useless. In fact, the answer is very simple, and the answer is not unique, as long as you can explain the calculation method. In particular, points out the issues that need to be paid attention to when designing the shape of the ID. This is a complete design guide.

Determination of the shape of the mobile phone

ID gets the design guidelines, first draws sketches for conception, and then concentrates on the selection of plans to determine the next two or three sketches, not only to meet the creative requirements of the customer, but also there are differences in style between the two and three sketches. Then go on the machine to refine and draw a complete rendering of the whole machine

Structural modeling

1. Data collection

To start modeling, MD requires ID to provide a wire frame. The wire frame is drawn by ID according to the outline on the process drawing, which can more truly reflect the design intent of ID. The output file can be in DXF and IGS format. If it is in DXF format, MD requires Place the wireframes of different perspectives in the CAD according to the orientation of the six views, so that they can be transferred into the UG trace

2. Idea disassembly

Before MD starts, we must first think about how to disassemble the mobile phone. An important idea in making a mobile phone is that there must be a main body in the casing of the mobile phone. The strength of the main body is the best, the thickness is the thickest, and the strength of the whole machine. It's all up to him. The other parts are attached to him. This kind of mobile phone structure is strong. The fixing of the main board also depends on the main body. If the upper shell is thicker and suitable for the main body, the main board is usually installed on the upper shell. , If the lower shell is thicker and suitable for the main body, the motherboard is usually installed in the lower shell

The disassembly should be simple and convenient. Excessive disassembly will reduce the strength of the mobile phone and increase the difficulty of assembly. After the disassembly plan is determined, the draft between the various shells must be considered. The upper and lower shells should be drawn out by more than 3 degrees.

3. Drawing of the exterior surface

The appearance surface refers to the outer contour surface of the mobile phone. A good curve makes a good surface. When drawing the line, it must be close to the ID wireframe. Respect for ID creativity is the basic cultivation of structural engineers. At the same time, the lines should be as smooth as possible, and the curvature should be changed. Try to be even

4. Preliminary disassembly

The disassembly at this time is to confirm the appearance and make the appearance of the prototype for the customer. It is not necessary to do the shell, but the parts that can be seen in the appearance should be drawn as separate, which is convenient for the appearance of the prototype to make different surface effects. The rounded corners should be rounded

5. Modeling data output

After the MD modeling is completed, make the six views of the whole machine in the engineering drawing, transfer the DXF wireframe file and feed it back to the ID to adjust the process annotation. The six-view wireframe of the completed mold may be modified from the wireframe provided to the MD by the original ID. , ID needs to be updated appropriately, and the process drawing is further completed, indicating the material and surface technology of each visual part Model 3D drawing, you can send out the appearance prototype.

Making and appearance adjustment of appearance prototype

The appearance of the prototype is made by a special prototype factory. It takes 3 to 4 days to make a straight phone. The appearance of the board is solid. It is not removable and is mainly used to confirm the appearance of the customer. Now the buttons of the appearance of the prototype can be cushioned at the bottom. The aberdeen film is matched with a feel, just like the real machine. After the customer receives it, the evaluation will be made, and the modification opinions will be given. After the MD is responsible for the improvement, you can start to make the internal structure.

Structural design

The refinement of the structure should start with the overall layout. I suggest that the overall structure of the structure should be planned first, that is, the stop line of the upper and lower shells, the structure of the screw column and the main buckle should be done first, and after these three steps, the frame of the mobile phone Just set it up. Then follow the order from top to bottom, from top to ground to complete the detailed structure. From top to bottom means that the upper shell components are completed first, and then the lower shell components are made, from top to ground.

1. The production of the stop line

At the beginning of the internal structure, the upper and lower shells are first extracted. In order to facilitate assembly, the male stop can be appropriately drafted or guided.

2. The structure of the screw column

The screw post is the key to determining the strength of the whole machine. Usually six screw posts are reserved on the motherboard. Don't waste it, use them as much as possible. Another important function of the screw post is to fix the motherboard and the side of the screw post. It is necessary to have ribs to clamp the main board, so that the structure is reliable.

3. The layout of the main buckle

4. Fixing structure of upper shell decorative hardware piece

5. Fixed structure of the screen

The screen is like the face of a mobile phone. It should be protected well and built a wall? By the way, it is to use the upper shell to come up with a circle of surrounding bones.

6. Fixed structure of earpiece

The earpiece is the sounding device of the mobile phone. It is generally located on the top of the screen. In addition to positioning, it also needs to have a well-sealed sound cavity. The structure uses the upper shell to make a circle of bones to surround the outside of the earpiece, which is similar to the outer bone of the screen, but the earpiece The surrounding bone does not have to support the main board, it is enough to cover 2/3 of the thickness of the earpiece. Then the upper shell is raised again to surround the sound hole of the earpiece, and the surrounding bone presses the foam on the front of the earpiece to form A relatively closed sound cavity, and finally a sound hole on the upper shell, the range of the sound hole of the upper shell should be within the range of the sound hole of the earpiece.

7. Fixed structure of the front camera

The front camera is located on the front of the motherboard, using PFC, and the connector is connected to the motherboard. The positioning of the camera is also located by enclosing the camera with a circle of bones on the upper shell. The camera is like the eyes of a mobile phone. In order to ensure a good shooting effect, the camera The front lens part needs to have a good sealing structure to prevent dust or foreign objects from entering and blocking the line of sight. We use foam to separate the lens from the inside of the case, and a transparent lens is added to the outside to ensure good quality. Light transmittance and wear resistance, the lens of the camera is made of glass, and the bottom is silk-screened. The purpose of the silk-screen is to cover the double-sided adhesive tape between the lens and the housing.

8. Fixing structure of power saving mode lens

The power-saving mode lens is less used. Some mobile phones have a power-saving mode setting. You need to open a skylight on the phone case so that the photosensitive ID inside can sense the brightness of the outside world. This requires opening a hole on the case and adding it. Cover the lens, the lens can be cut with PC sheet and directly attached to the outside of the case, or it can be made into an injection molded light guide and fixed by hot glue on the inside of the case.

9. Fixed structure of MIC

The MIC is located at the bottom of the mobile phone, just like the ear of the mobile phone. It is a component that converts external sound into electrical signals. Therefore, it is necessary to allow the external sound to be transmitted to the MIC without hindrance, and at the same time to prevent the influence of the sound from the internal cavity of the case. When it comes to the MIC, the surrounding bone is indispensable in the structure. At the same time, the MIC itself must be wrapped by a rubber sleeve, and only a small hole is exposed in the front to sense the sound. The front must also be well-fitted with the shell, and the guide on the shell The sound hole generally has a 1.0mm round hole. The connection between the MIC and the motherboard can be wire bonding, FPC welding or through welding on the motherboard.

10. The structure design of the main button

The main buttons of the mobile phone can be divided into ultra-thin buttons and conventional buttons according to the thickness. In the past, when the flip machine was used, the thickness of the slide machine was limited, and the thickness of the button was less than 2mm. The structure of the sheet and silica gel was used directly. It can be a thin steel sheet or a PC sheet. In order to ensure that the buttons are not linked, the different function keys on the sheet will be separated by through holes (such as the main button of the V3 mobile phone). The function is to get a good button feel.

Nowadays, there are most of the candy bar machines in the market. I will take the P+R button as an example to talk about the structure design of the main button, and divide the structure design workload of the candy bar machine into 100 parts. I think the structure design of the button assembly accounts for 30%. , The upper shell component accounts for 30%, the lower shell component accounts for 40%, which shows the importance of the buttons. The P+R button includes three parts: the keycap component, the bracket and the silicone. Some buttons are added between the keycap component and the bracket. A piece of shading paper prevents light transmission between the keys.

The bracket material is determined according to the thickness of the button. It can be injection molded with PC or ABS, with a thickness of 0.8-2.0mm; it can also be directly punched with PC sheet, with a thickness of 0.5, 0.6 or 0.7mm; when the button thickness is not enough, the bracket material Use a 0.15mm thick stainless steel sheet, but considering the impact of the steel sheet on the motherboard during ESD (electrostatic test), we need to bend a section of cantilever on both sides of the steel sheet, which is connected with the grounding net on the DOME sheet, or with the button PCB The grounding copper foil on the upper part is connected, the thickness of the silicone sheet is 0.3mm, and the long boss on the front is matched with the glue on the keycap. The DOME pillar on the back is matched with the nest piece.

11. Structural design of side buttons

The side buttons are located on the left and right sides or top side of the phone. The functions are usually the volume button, the camera button, the power button or the lock button. The structure is simpler than the main button. The position of the side button on the motherboard is usually fixed by welding. A mechanical button with lateral contact, one mechanical button corresponds to one function. The advantage of the mechanical side button is that the structure is simple and the hand feels good. There are also FPC buttons. The pad position is reserved on the motherboard and the FPC is fixed by surface welding. The key board, the FPC key board is bent to the side, and the nest piece on the key board can be inductively pressed. The advantage of the FPC side key is that the center position of the side key can be slightly adjusted as needed when the main board is unchanged.

The structural design of the side button part usually adopts the P+R form. Compared with the main button, the side button does not need to be a button holder. The silicone part must help to improve the feel and not be hard, and the keycaps are often equipped with skirts to prevent them from falling out. The surface treatment of the keycaps can be primary color, oil injection or electroplating. Because there is no LED light, the side keys do not require light transmission, and crystal keycaps are rarely made. The functional characters are generally made on the keycaps by engraving.

The side button is fixed by extending an ear on the side of the side button, and then clamped by the shell extension bone. This is mainly to prevent the button from loosening during the assembly process of the whole machine. Once the shell is closed, the clamping part of the side button It basically has no effect, and the fit clearance of the clamping part is zero.

12. Structure design of USB rubber plug

The USB rubber plug is used to protect the cover of the USB connector. In order to facilitate opening and closing, usually softer TPE or TPU materials are used. The structure of the USB rubber plug is divided into four parts: the body, the handle, the tongue, and the positioning column. It is black or uses a color close to the shell. The functional characters of the USB are engraved on the body. The hand grip can be extended or dig a piece to make it concave. The tongue part is the USB rubber plug to prevent it from extending into the USB connector. The loose rubber bone, the positioning post is the inverted buckle of the USB rubber plug fixed on the shell, which can be made into an external plug-in type or a direct pressure type (directly stuck between the shells).

The similar structure on the mobile phone also has the rubber plug of the T-FLASH card or the SD card. The longer rubber plug can also be made into a P+R structure, that is, the body, the hand part is made of hard rubber, and the inside is inserted and fixed. Some are made of soft glue, and the hard glue and soft glue are glued together.

13. Structural design of screw hole rubber plug

The exposed screw cap on the surface of the mobile phone will affect the appearance and must be covered with a screw hole rubber plug. The screw cap in the battery cover can not be covered. The structure of the screw hole rubber plug is relatively simple, and the mold can be placed in the same mold as the USB rubber plug. Inside, it is made by a mold factory. The screw hole rubber plug is approximately cylindrical. For convenience and easy access, the inside can be hollowed out. The outer surface of the screw hole rubber plug must be consistent with the contour surface of the shell, and the diameter should be as small as possible (than the screw The cap diameter is larger than 1.0mm). If the outer surfaces of the left and right screw hole rubber plugs are not the same and cannot be interchanged, a fool-proof groove must be made on the cylindrical surface of the screw hole rubber plug to distinguish.

The screw hole rubber plug can be made eccentric with the different axis of the screw according to the needs of the structure, as long as it can cover the screw cap.

Because the disassembly of the whole machine must use screws, in order to verify that the phone has not been disassembled privately, some manufacturers will dig a platform on the top of the screw hole in the battery cover and attach a piece of fragile paper. If you want to loosen the screw The screw in the hole must destroy the fragile paper. The platform for the fragile paper must be designed according to the size of the fragile paper. The shape of the platform is slightly larger than the fragile paper, and the position is lower than the shell by one level to prevent accidental fingers. Fragile paper is touched in.

14. Fixed structure of horn

The volume of a mobile phone is a strong selling point, which puts higher requirements on the sound cavity of the speaker. In addition to requiring the solution company to tune the output of the speaker itself to the best condition, the sound cavity structure of the speaker also needs to pay attention to several points:

a. The front sound cavity of the horn must be closed. If the horn and the shell are directly matched, the horn and the shell must be sealed with a ring foam, and the side of the horn must be surrounded by the long ring bone of the shell. Leave 0.1mm edge clearance.

b. The height of the front sound cavity of the horn should be greater than 1.5mm. The sound cavity height of the horn refers to the vertical distance from the front of the horn to the inner wall of the shell. In order to ensure a sufficient height of the horn sound cavity, the inner side of the sound cavity of the shell can even be thickened. Cut out the thickness to 0.6mm.

c. The area of ​​the sound hole must reach 15% of the sound area of ​​the speaker, and the sound hole area is the sum of the total area of ​​the sound hole.

d.The simplest way to structure the sound hole is to open holes directly on the shell, which can be an array of circular holes or a set of elongated holes.

e. The rear acoustic cavity of the horn mainly affects the low-frequency part of the ringtone, but has a small effect on the high-frequency part, so it is not required.

15. Fixed structure of lower shell camera

The fixing structure of the lower shell camera is similar to the fixing structure of the upper shell camera. Both use PFC or connectors to connect to the motherboard. Positioning requires surrounding bones, and sealing requires foam and lenses, but the difference is that the positioning of the lower shell camera is by means of an antenna bracket. , The antenna bracket surrounds the periphery and bottom of the lower shell camera to fix the camera. In order to ensure that the center of the lower shell camera and the shooting hole center of the lower shell are not offset, the lower shell positioning surrounding bone is still necessary. The lower shell camera lens is also installed complete Blow off the mirror dust after the machine, and then install it at the end.

16. The structure design of the lower shell decoration

The decorative parts of the lower shell can be plastic, IML parts, hardware pieces, etc.

The surface of plastic decorative parts can be made of electroforming effect. The advantages are strong metal feeling, high grade, good wear resistance, plastic decorative parts are directly hot glued or buckled on the shell, and the thickness is 0.9~1.0mm. IML parts are just a combination of existing ones. The FILM with silk screen pattern is placed in a plastic mold for injection

The thickness of the stainless steel decoration is 0.2~0.3mm, and the hardness is higher than that of the aluminum decoration. The color used to be single, but with the development of technology, the color has gradually become richer. Other surface treatment effects of stainless steel decorative parts mainly include wire drawing, high gloss (mechanical polishing), pitted surface (sandblasting), matte, etc.

17. Structural design of battery box

The battery is the place where the mobile phone stores energy. It is required to be easy to install, have good contact, not fall out, and be easy to take. The structure of the battery box must meet these requirements:

a. The basic material thickness of the battery box is 1.0mm. The bottom of the battery box should be closed as much as possible. If there are components, avoid components. If there are no components, try to cover them with plastic shells to avoid exposing large PCBs.

b. Gap, the unilateral gap in the pick and place direction is 0.2mm, the draft is 3~5 degrees, the unilateral gap in the non pick and place direction is 0.1mm, and the draft is 1 to 2 degrees. The gap between the bottom of the battery box and the battery is 0.1mm The gap between the plastic shell at the bottom of the battery box and the patch components is 0.2mm, and the gap between the plastic shell at the bottom of the battery box and the SIM card connector is 0.5mm.

c. The two ends of the battery loading and unloading direction need to be buckled with the battery to prevent loosening. The amount of buckle can be evaluated according to the rotation of the simulated battery loading and unloading. Leave a dent slightly wider than the nail when the hand is pulled. It is convenient for fingers to pull out the battery.

d. The battery box should protect the battery connector, that is, after the battery is placed in the battery box, only the shrapnel of the battery connector can be touched, and the body of the battery connector is not allowed to touch the battery connector to avoid damage to the battery connector during the drop test.

18. The structure design of the motor

The motor is an electronic component that generates weak mechanical vibration on the mobile phone. When the user sets the mute, the user can sense the incoming call through the vibration of the motor. The shape of the motor is divided into cylindrical and flat. The connection methods mainly include wire bonding, shrapnel, and SMT type and plug-in type.

19. The structure design of the stylus

The stylus is only used on mobile phones with a touch screen. It is generally fixed on the lower shell and pulled out when using it. The stylus is divided into a cap, a barrel and a nib. It is convenient to draw the pen out. The pen tube is a hollow stainless steel tube or a copper tube, which can be made into one section or multiple sections according to the needs. The pen tip has a ring of grooves, and it is positioned by the groove after inserting into the lower shell.

20. Structure design of battery cover

The battery, SIM card and T-FLASH card should be designed to be replaceable, hide them in the battery box of the lower shell, and then design a battery cover that can be easily opened and closed to protect them. The material of the battery cover can be plastic. The surface can be affixed with decorative parts such as lenses or hardware, or it can be bent with stainless steel sheets. The structure of the battery cover includes the handle position, the buckle, the side buckle, the dial point, and the handle position is used when removing the battery cover. The place of force, the buckle and the side buckle, are the structure that the battery cover snaps into when it is inserted into the lower case, and the shift point is the locking structure that prevents the battery cover from exiting after being inserted into the lower case.

20. Structural design of the rope hole

The rope hole is a structure used to fix the sling on the mobile phone. A lightweight mobile phone can be hung on the chest with a lanyard, but now with the increase of hardware decorations on the surface of the mobile phone, and the increase of the battery volume caused by the long standby time, This has caused the weight of the mobile phone itself to gradually increase, and some customers no longer require a lanyard hole. Anyway, I do not recommend that you hang the mobile phone on your chest. Except for the security environment here, the mobile phone battery is not safe. Gradually worrying about more and more people, let's put it in your pocket!

The structure of the rope hole is generally made in the lower shell, and the pin is seen in the neutral position of the antenna bracket. The position is indispensable, and the bone position that covers the lanyard has sufficient strength.

Data collation of quotation chart

To do this, the structural design of the mobile phone has temporarily come to an end, and one important thing is to be done first-to provide customers with a plastic mold quotation map. It takes about 18 days to make the plastic mold, which is the top priority of the entire mobile phone project. Before that, it took a few days for the customer to select a mold factory. First, hand the preliminary completed structure diagram to the customer to contact the supplier. This can shorten the time for the entire project process. We use the customer to contact the supplier for a few days. The product can be optimized, reviewed and modified, and when the customer selects a supplier, our structural design has also been completed, which coincides with the mold supplier entering the mold review stage.

Structural design optimization

Okay, now we can calm down and optimize our structural design. The design plan is to become a product. There are many problems that we need to think about and prevent, such as whether the surface hardware needs to be grounded; what is the relationship between the main board and the shell Coordination; how to increase the strength of the shell; how to improve the shell to facilitate mold making and so on.

Structure review

Every structural engineer makes a design, there are always problems that he can't discover, and need to be checked by other engineers. The location is different, the angle of observation is different, and the judgments drawn will be different. If you make a mistake, you can correct it. If you have any questions, please discuss it with everyone, which can make the level of the drawings to a higher level. During the review, another structural design engineer will conduct a preliminary review of the drawings. The preliminary review takes about half a day to a day. The drawings need to be evaluated from appearance to plan. , Upper shell components, lower shell components, surface technology, mold feasibility, and the order of production and assembly are comprehensively inspected one by one, and the problem points are recorded. Then enter the second stage-collective review, which is composed of all members of the structure department The meeting where relevant ID designers participated together listed the issues of the preliminary review, and everyone expressed their opinions and unified understanding, which not only ensured that the drawings issued could represent the highest level of the company, but also provided an opportunity for structural design engineers to learn and improve. In Shenzhen, the larger the design company, the more important the role of collective review.

Structural prototype verification

No matter how well the previous structure is done, it is just a matter of paper. The structural design needs to be verified with the help of physical objects. The structural prototype plays a role in verifying the structure. The data for the structural prototype includes ID process annotation, BOM and 3D drawing files (of course, it is still (To convert to STP format), it takes about 4 days to make the structural prototype, and the appearance and size are required to be consistent with the drawings, so that it is closer to the final prototype. Get the structural prototype with the motherboard and battery. This is a real mobile phone. Now, don’t be too happy, check the size of the parts carefully to see if there is any problem with the assembly of the whole machine, and whether there is any improvement to make the production more convenient and faster. Now, be careful and the mold will be smoother in the future.

Mold review

Doesn't it take 4 days to make the structural prototype? During this time, we can send the ID process marking, BOM and 3D drawing data to the customer, and the solution company and the selected mold factory will be reviewed. This review generally takes 1`2 days. If customers have their own technical strength, they can check again. The solution company can evaluate the possible problems in the antenna signal reception, and the mold factory will put forward some suggestions for improvements that may occur in the mold making, and feedback the improvements to the design. The company. When necessary, the customer will meet with the design company and the mold factory to discuss the improvement opinions of the mold factory, and the problems that need to be paid attention to when the mold is opened can be raised. The design company and the mold factory have the final decision and the result is discussed. Submitted to the customer in triplicate, the design company and the mold factory keep the records separately, the design company updates the drawings based on the results of the discussion, and sends out a formal mold opening drawing, which includes the final ID process mark, BOM and 3D drawing.

Project follow-up during casting

It takes about 18 days for the plastic parts to open the mold. Is it all right to do during this time? Of course not. In addition to the plastic parts, the mobile phone supplier also has buttons, hardware, lenses, nickel sheets, batteries, stylus pens, and accessories. Wait, as long as it is used on this phone, it can't be less.

Trial and Modification

Let’s take plastic parts as an example for explanation. Mold trial and mold modification are the plastic parts trial production and mold trimming performed by the supplier after the mold is made to meet the design requirements. The customer will follow up the samples of other accessories before the mold trial. When testing the mold, we will go to the mold factory with the structural design engineer. The structural design engineer conducts single product inspection and mounting inspection on all accessories. The single product inspection includes appearance defect inspection and dimensional inspection. The mounting inspection is to make all accessories according to the actual production. The assembly sequence is implemented to find out the problems. All problems are listed in turn, coordinate with the mold factory, determine the improvement plan, improve the time and the person responsible for the improvement, the design company and the mold factory have disputed issues by the customer to make the final It is decided that the results of the discussion will be signed and copied and submitted to the customer in triplicate. The design company and the mold factory will keep the records separately. The design company will update the model modification drawings based on the discussion results and issue a formal model modification plan. The model modification plan includes detailed text of the model modification part. Explain that the 3D drawings of the parts that need to be remodeled. The parts that require remodeling on the 3D drawings must be marked in red. The problems of the remodeling are not large or small, and must not be omitted.

Trial production

The improved samples will need to repeat the trial mold procedure for inspection, but this time the trial mold upper, lower shell and other appearance accessories can be surface treated (for example, the ID process drawing indicates that the surface is sprayed, UV, oxidized, wire drawing , Screen printing, electroplating, laser engraving) and then install it. If the installation is confirmed to be correct, you can schedule trial production.

Mass production

After many demonstrations, modifications, inspections, and modifications, the results of the hard work of the structural design engineers are about to come out. All the problems have been solved before mass production. If there are no problems, the process of mass production does not require structural design engineers. Participation, according to current market conditions