Selection of spot welding pliers in automobile manufacturing

In automobile manufacturing, mobile spot welder is car body welding automation production line, the main equipment for automotive body compound task executing agency for point electrode holder, welding reasonable option electrode holder model can realize welding equipment and operation personnel quantity reasonable, easy operation, reduce the labor intensity effect, so the point electrode holder selection is very important.Automobile body spot welding is the main form of resistance welding. There are three main types of spot welder: common spot welder, multispot welding machine and spot welding robot.Ordinary spot welder is a universal spot welding equipment suitable for all kinds of occasions and welding objects. It is divided into movable spot welder and stationary spot welding machine according to the machine structure and application situation.Portable spot welder is car body welding automation production line, the main equipment for automotive body compound task is suitable for the welding structure of large size, complicated shape, not easy to move the weldment and large thin-walled workpiece structure, welding actuators for point electrode holder.Spot welder type spot welding pliers can be divided into X - type welder and c-type electrode holder (FIG. 1, 2).

图1X型焊钳
 

图2C型焊钳

     In the first place in the table according to the engineering work of welding parts, production rhythm design determine the number of point electrode holder, high tempo, the number of point electrode holder set, otherwise, as far as possible reduce the number of point electrode holder, reasonable division of each point electrode holder job content, and then on the basis of product structure, the structure of the fixture, job position, etc. To determine the reasonable point electrode holder type.The x-type spot welding electrode is used for spot welding level and near horizontal position of solder. The movement of the electrode is the arc line.The c-type spot welding pliers are used for spot welding vertical and near-vertical solders, and the electrodes are in straight line motion.In general, the welding point is more than 300mm at the edge of the product, and the x-type welding pliers are selected. The welding point of the solder is less than 300mm.

    Electrode pressure: the electrode pressure belongs to the field of welding parameters. The size of the electrode pressure is mainly related to the material of the welding part. The table is the welding parameter with electrogalvanizing steel plate and low carbon steel plate as the example.The electrode pressure of spot welding pliers can be used to meet the pressure of the highest electrode in the pad group

    The extreme pressure is 1470 ~ 4900N.

 Spot welding pliers: spot welding tongs to separate working trips and auxiliary trips.Working stroke directions electrode holder normal ventilation condition open distance of two electrodes, the smaller the work schedule, when welding the higher work efficiency, so where possible, try to choose a smaller work schedule;The auxiliary stroke refers to the distance between the two electrodes of the electrode holder when the handle is pushed or pressed by the air valve button.With parts to avoid point electrode holder into the welding position, welding fixture, such as interference, using point electrode holder auxiliary stroke point electrode holder into the welding parts, namely auxiliary trip point electrode holder into the welding position open, two electrode spacing, into close auxiliary trip after welding parts, point to implement welding electrode holder.Shown in figure 3 point of welding parts, electrode holder into the welding position requires two electrode distance is greater than 280 mm, if not using auxiliary stroke, the production efficiency is low, welding force is big, the welding position, quality assurance.In order to improve production efficiency, product structure, the structure of the fixture licensing, such as work schedule under the condition of no greater than 50 mm, try not to use the auxiliary trip, choose a big work schedule of the electrode holder, auxiliary stroke are consistent with the size of the work schedule at this time.

图3 焊接部位示意图

     Point electrode holder arm size: point electrode holder arm size refers to door deep (wide), high dimension (as shown in figure 4), determined by the product structure, often to avoid the interference of point electrode holder arm and parts, reduce the welding, the distance between the electrode holder arm to parts keep in more than 30 mm.To meet the various welding process requirement of the premise, point gate electrode holder arm deep (wide), the door is high size set, follow the principle of size as small as possible, can reduce the weight of the electrode holder, easy operation, reduce the labor intensity.

图4X、C型点焊钳臂规格尺寸

     In determining the point electrode holder arm deep (wide) door, the door is high dimensions, at the same time, according to the product structure, the structure of the fixture consideration: 1. The electrode shape, length, Angle and so on, in the case of using high frequency, electrode use replaceable electrode cap as far as possible, reduce the use cost;2. To avoid interference with soldering arm and making parts, welding clamps, etc.Figure 5 shows an example of a type C spot welding pliers with various elements, and detailed rules for the size of the relevant parts.

图5C型点焊钳臂相关部位尺寸

     3d simulation: after the above project is determined, the model of the welding pliers is basically determined, and the corresponding welding pliers can be designed according to various specifications.Will design the 3 d point electrode holder and point electrode holder accessories, products, such as d/a, clamp in the 3 d software, the simulation job position, the following main job content confirmation of the project: 1. The point electrode holder can enter the welding parts for welding;2. Whether the welding pliers and accessories should be interfered with the product number, fixture, etc.3. Is it convenient to work?4. Is it reasonable to replace, remove and flip the electrode holder?After the confirmation of the improper project, the modification plan should be made, such as the number of reconfirmed spot welding pliers, type and negotiation welding jig, spot welding pliers, etc.The correct selection of spot welding pliers can make the number of equipment and operating personnel reasonable, the welding part is convenient and the labor intensity is low.If the electrode holder models not suitable degree can't meet the requirements of welding technology, the need to the option electrode holder models, increased investment costs, extend the production preparation period, visible point electrode holder type of right choice is very important.Before the 3d software is widely used, the selection of spot welding pliers is generally 60 to 80 percent, while the selection of spot welding pliers with the above elements can achieve more than 90 percent accuracy.