How to choose a suitable manipulator for injection molding machine for household appliances injection molding manufacturers?

The general characteristics of injection-molded parts of household appliances (shell, panel, base, interior decoration, etc.) are large size, high appearance requirements, often with inverted buttons/deep cavities, multiple inserts, large batch and stable rhythm. The core of choosing a special manipulator for injection molding machine is: matching the tonnage of injection molding machine → selecting the number and structure of shafts according to the product/process → calculating the load/stroke/accuracy → looking at the drive and control → paying attention to after-sales and flexibility.

First, match the injection molding machine: tonnage, clamping force and installation space.

1. Tonnage → Load and Travel (Core)

50–150 tons (small household appliances/accessories)

Load: 1–3 kg; Horizontal stroke 800-1200mm；; Vertical 500–800 mm

Model: oblique arm, three-axis servo small

150–300 tons (conventional household appliance shell/panel)

Load: 3–8 kg; Horizontal 1200–1800 mm; Vertical 800-1200mm

Model: 3-axis/5-axis servo single/dual arms

More than 300 tons (refrigerator/washing machine/air conditioning shell)

Load: 8–50kg+; Horizontal 1800–3000mm+; Vertical 1200–2000 mm+

Model: five-axis servo, bull's-head, large transverse, six-axis multi-joint.

2. Key installation and interference inspection

Rod spacing (Corinthian column): arm width of manipulator < rod spacing (leave 10–20mm safety clearance).

Mold thickness/mold opening stroke: the vertical stroke must cover the highest point of mold opening+product ejection height.

Workshop height/crown block: if the height is insufficient, choose side-take/vertical-walk or short fuselage model.

Cycle matching: cycle time of manipulator ≤ injection cycle (2-3 seconds allowance is recommended).

Second, choose the number of shafts according to the product and technology: 3/5 shafts are most commonly used in household appliances.

1. The number of axes and degrees of freedom (directly determine the ability to move)

Three-axis servo (X/Y/Z: translation) is applicable to: conventional household appliance shells, flat parts, simple parts taking, multi-cavity die and nozzle separation Advantages: stability, speed and high cost performance (90% of household appliances are universal) Positioning: 0.1–0.2 mm.

Five-axis servo (X/Y/Z+pitch R1+rotation R2) is suitable for: with inverted/deep cavity, need to rotate demoulding, insert embedding, flip stacking, two-color/die stacking, water intake of main and auxiliary arms. Typical household appliances: washing machine/air conditioning shell, refrigerator liner, ribbed complex shell. Advantages: free angle, scratch resistance and complex demoulding.

Six-axis multi-joint application: super-large, complex deep cavity, multi-pose assembly, long stroke, high cost of flexible production line, which is generally used for large/high-end household appliances.

2. Structure type (commonly used in household appliances)

Traverse (servo): mainstream, high precision, stability and suitable for long stroke.

Oblique arm type (pneumatic/servo): small tonnage, low cost and simple picking.

Tau type: mainframe, extra wide/extra long parts (air conditioner, refrigerator panel)

One arm/two arms: three-plate die/overlapping die/two-color die must have two arms (main intake+auxiliary intake).

Third, the core performance parameters (home appliances must see)

1. Load calculation (margin must be reserved)

Total load = product weight+fixture weight+nozzle weight

Safety margin: ≥ 20–30% (long-term heavy load is easy to lose accuracy and damage the motor)

Example: product 5kg+fixture 2kg → load model ≥8.4kg.

2. Three elements of the trip

Horizontal (X): Covering mold width+blanking position/conveyor belt

Vertical (z): mold opening stroke+ejection stroke+safety height.

Drawing (Y): Reach into the mold depth (the deep cavity should be lengthened)

3. Accuracy and speed (key to appearance of household appliances)

Repetitive positioning accuracy:

Ordinary parts: 0.1–0.2 mm

High gloss/precision/assembly: ≤±0.1mm

Speed and smoothness:

Batch line of household appliances: cycle for 3-8 seconds; High-speed thin wall is shorter

Choose full servo (motor+reducer+linear guide rail), with smooth movement and no jitter and scratch.

4. Drive and control

Drive: Full servo motor is preferred (higher precision, longer service life and stability than pneumatic/semi-servo).

Control:

Special manipulator controller (with touch screen)

Support multi-program storage (100+molds)

On-line signal and safety interlock with injection molding machine

Optional: CCD visual positioning/defect detection, MES docking and remote diagnosis.

4. Fixture and terminal (scratch prevention of household appliances is the most important)

Most household appliances are high-gloss/matte/dermatoglyphic, and scratches and indentations are strictly prohibited.

Suction cup:

Large area/flat parts: vacuum sucker (soft silica gel/PU)

Note: multi-suction point balance, anti-deformation, anti-residual printing

Clamping jaw:

Structural members/corners: flexible jaws (covered with soft rubber/silicone rubber sleeve)

Avoid hard contact and adjust clamping force

Special:

Deep cavity/inverted buckle: pneumatic finger and rotatable claw.

Insert (nut/copper sleeve): pneumatic clamp+positioning

V. Brand and Budget (Reference for Home Appliances Industry)

1. Brand echelon

International: STAR, Yushin, hamo, wittmann (top precision/stability, high price)

Domestic first line: Siweike, Bronte, Tuosida, Jiejia, Apocalypse Star and Bo Zhiya.

Advantages: high cost performance, suitable for household appliances, fast service and customization.

Domestic second line: suitable for small batch and ordinary parts.

2. Price range (2026)

Three-axis servo (50–300t): 50–150,000.

Five-axis servo (150–500t): 150–300,000.

Large/Tau/Six Axes: 300,000–600,000+

Six, household appliances industry selection quick look-up table (direct comparison)

form

Product Type Recommended Axles Recommended Structural Load/Accuracy Core Points

Small household appliance shell/panel/cover three-axis servo traversing single arm 3–8kg/0.1mm is fast, stable and scratch-proof.

Air conditioner/washing machine shell five-axis servo traverse arms/bull's head 10–30kg/0.1mm long stroke, rotary demoulding.

Refrigerator liner/drawer with 5-axis/6-axis traverse/multi-joint 8-20kg deep cavity and deformation prevention.

With insert (nut/metal) five-axis servo+positioning belt, the rotating shaft is embedded accurately and the posture is adjustable.

Two-color/overlapping mold/three-plate mold five-axis double-arm main and auxiliary arms take parts synchronously+high efficiency of nozzle and less labor.

Seven, purchase and acceptance steps

Provide parameters: tonnage of injection molding machine, clamping force, distance between tie rods, mold size, product weight/size/cycle, appearance/process requirements.

Manufacturer's plan: model, number of shafts, load, travel, fixture plan and cycle checking.

On-site commissioning:

Actually, the parts are taken smoothly/without jitter/scratch.

Run continuously for more than 2 hours to measure stability.

Verification of Safety Door, Emergency Stop and Overload Protection

After-sales: 24-hour response, local service, 1-2 year warranty and training.

Eight, avoid pit points

Only look at the cheapness and ignore the load margin/accuracy/rigidity: after half a year, it is inaccurate, scraped and highly maintained.

Insufficient number of shafts: complex parts can't be taken out, die bump, and manual repair.

Hard contact of fixture: appearance scrap rate soared

Mismatched injection cycle: bottleneck of production line and inability to increase production capacity.

summary

Manipulator for home appliance injection molding: three-axis servo for small/conventional parts, five-axis servo for large/complex parts, and six-axis servo for large/ultra-complex parts; Full servo, full load, long stroke, high precision, soft fixture and good service. Priority is given to domestic first-line brands with many cases of home appliances, which can be customized and sold quickly, and the cost performance and stability are the most balanced.