What are the differences between single-arm and double-arm of three-axis servo manipulator?

Three-axis servo manipulator: the core difference between single-arm and double-arm

Three-axis servo traverse manipulator is widely used to take out products and material heads in injection workshop, and single/double joints refer to the telescopic structure of upper and lower arms; One-arm/two-arm refers to the number of arms, which are two independent concepts, and are easily confused in many types selection.

One section VS two sections (upper and lower telescopic arm structure)

Single arm (single-cut)

The single section is a whole integrated arm, which can be extended and retracted in a single section without an intermediate plane joint. When the arm is retracted, the total height of the whole machine is large.

1. Plant height: The requirement for the clear height of the plant is high, which is suitable for the scene with sufficient plant height. In the retracted state, the overall height of the equipment is high.

2. Stiffness and accuracy: integrated profile, simple structure, good rigidity, small jitter and good repeated positioning stability; The deformation resistance under long stroke is better than that under double section.

3. Travel speed: the same up-and-down travel, long mechanical travel and slightly longer overall cycle period.

4. Maintenance: few parts, few belt speed doubling mechanisms, few fault points and simple later maintenance.

5. Adapted tonnage: mostly used for small and medium tonnage injection molding machines, with a common tonnage of 50,280 t; The Great travel itinerary Festival puts great pressure on the height of the factory building.

6. Cost: The price of the same specification is lower.

> application: the workshop is full of floors, with two boards, giving priority to the rigidity and stability, and the budget is limited, and only the finished products or the material heads are taken.

Double-jointed arm (double-cut double-speed type)

Adopt two-stage nested telescopic+double speed belt mechanism to realize short retraction height and large effective up-and-down stroke.

1. Plant height: the height of the whole machine is greatly reduced after retraction, which is suitable for low-rise plants and workshops with insufficient floors.

2. Rigidity and accuracy: Two-segment sliding nested structure, with the same cross-sectional area, the rigidity is slightly weaker than that of a single segment; Do a good job of guide rail maintenance, which can meet the requirements of conventional precision picking.

3. Travel speed: double-speed structure, achieving half the retraction distance, faster up-and-down action response, shortening the overall picking cycle, suitable for high-speed thin-walled product production.

4. Maintenance: one more sliding pair and double speed belt; The belt belongs to wearing parts, so it needs to be checked regularly for tension and replacement.

5. Adapted tonnage: 50,450 t is acceptable. For large tonnage and large up-and-down travel, two sections are preferred to avoid the height limit of the workshop.

6. Cost: slightly more expensive than a single arm of the same specification.

> application: the height of the workshop is limited, the three-plate mold, high-speed short-cycle products, need a large up-and-down stroke.

Second, one arm VS two arms (number of arms)

single-arm

There is only one set of main arms and one set of jigs; Only one set of pick-and-place actions can be completed at the same time.

1. Working logic: Take the workpiece out of the mold, put it on the assembly line/material table after exiting, and then return it to the mold.

2. Advantages: simple structure, small volume, low cost and simple debugging.

3. Short board: it is impossible to grab the finished product+material head at the same time; The three-plate die needs to take the finished product first, and then go back to take the material head to increase the cycle time.

4. Application: two-die, only take the finished product, or only take the material head, the product is simple and the rhythm is loose.

# Double arms (main arm+auxiliary arm)

The same horizontal slide carriage is equipped with two independent arms, which can move synchronously: one clamping the finished product and the other clamping the nozzle head, which can enter and exit the mold at one time, and at the same time, the finished product and the head are taken out and placed separately.

1. Advantages: the efficiency of the three-plate mold is obviously improved, and the finished product is separated from the material head by one-time entry and exit, saving one-time in-mold entry and exit; You can do simple post-processing (water cut and insert placement) while blanking.

2. Short board: the equipment has greater self-weight and takes up more space; The cost is higher and the debugging is relatively complicated.

3. Applicability: Three-plate mold, one mold with multiple cavities, which requires the separation of finished materials and the pursuit of shortening the molding cycle.

III. Comparison of Four Combinations (Selection Comparison Table)

1. Single arm: integrated single arm, single arm. The factory building is high enough, with two boards and molds, budget priority, small and medium tonnage, and only finished products are taken.

2. Single-arm: Single-arm telescopic structure with two arms. Sufficient floor height, three-plate mold, pursuit of rigidity, need to take finished products+material head at the same time.

3. Double-section single arm: double-speed double-section telescopic, single arm. The height of the factory building is not enough, and it is two-plate mold, pursuing high-speed picking.

4. Double arms: double-speed expansion and contraction+double arms. Low-rise workshop+three-board mold is the most commonly used; Considering low retraction height, high speed and synchronous take-out of finished material head, it has the strongest comprehensive performance and the highest price.

Four, the key points of selection

1. First, confirm the effective clearance height of the workshop, and judge whether it is single section or double section;

2. Confirm whether the mold is a two-plate mold or a three-plate mold: the three-plate mold gives priority to two arms; Two plate molds can choose single arm;

3. High-speed thin-walled products give priority to double-jointed arms; Long stroke gives priority to evaluating rigidity;

4. Double-section models regularly check the tightness of double-speed belts; Two-arm models should pay attention to the interference and avoidance of two arms.

> simple summary: according to the height of the factory building, it is determined as "single section/double section"; Look at the mold structure (two plates/three plates), whether to take the finished material head at the same time, and decide "one arm/two arms".