Resistance Welding

Diakont delivers the DA99 and DA78 series electric servo actuators with specialized options to accommodate the unique requirements of the welding industry. Driven by an integrated motor and high-quality roller screw, Diakont actuators deliver best-in-class performance in a compact form factor. Diakont’s electric servo actuators deliver the high forces required for weld gun actuation with a high force repeatability.

Spot Welding Actuator Brochure

Strong, Consistent Force for Maximum Productivity and Weld Quality

Integrated Design
Optimized 10-Pole Motor
High Quality Roller Screw

Reduced weight
(from 6.7 kg / 14.8 lb)

Compact design
(from 78 x 78 x 285 mm / 3” x 3” x 11”)


High force
(up to 22 kN / 4,946 lbf)

High speed
(up to 750 mm/s / 29.5 in/s)



Optimized roller screw thread designs, machining accuracy, and hardening technologies (plasma nitriding) ensure actuators’ rugged endurance, mechanical load durability, and deliver 30M+ welding cycles

High Force and Productivity

Diakont servo actuators with 10-pole motors deliver higher peak force (22kN vs 17.8 kN) or more welds per minute ( 25 welds/min vs 20 welds/min) at similar force when compared with other roller screw actuators of similar sizes with 8-pole motors.

High Performance for Steel and Aluminum

Diakont actuators with 10-pole motors provide the capabilities for welding steel, aluminum, and dissimilar metals in a single solution. The optimized motor design provides forces up to 22 kN, which is ideal for welding higher gauges of steel and delivers improved productivity, increasing the number of welds achievable in a given time frame. This technology also allows for highly accurate force repeatability which is ideal for consistent aluminum welds. The ability to increase force by 9 kN in just 16 milliseconds facilitates successful welding of dissimilar metals by increasing from an ideal welding force to the ideal forging force in the necessary amount of time.

Diakont’s standard product line of weld gun servo actuators is outlined in the following table. However, Diakont’s engineering team often tailors existing designs to meet specific application requirements.
Model DA99-W25 DA99-W212 DA78-35
Peak force N (lbf) 22,000 (4,946) 8,800 (1,978) 13,000 (2,923)
Cont. force rating (stall) N (lbf) 9,700 (2,181) 4,300 (967) 4,600 (1,034)
Max. speed mm/sec (in/sec) 300 (11.8) 750 (29.5) 300 (11.8)
Transmission ratio mm/rev (in/rev) 5 (0.2) 12.5 (0.5) 5 (0.2)
Dynamic load rating N (lbf) 56,000 (12,589) 48,200 (10,836) 33,500 (7,531)
temperature range
°C (°F) 0 to 45 (32 to 113)
Strokes mm (in) 150 - 400 (5.9 - 15.7) 150 - 400 (5.9 - 15.7) 150 - 300 (5.9 - 11.8)
Weight* kg (lb) 10.6 (23.4) 10.6 (23.4) 6.9 (15.2)
Dimensions** mm (in) 99 x 99 x 320 (3.9 x 3.9 x 12.6) 99 x 99 x 320 (3.9 x 3.9 x 12.6) 78 x 78 x 285.5 (3.1 x 3.1 x 11.2)
Lifetime*** Welding cycles 16,000,000+ 30,000,000+ 30,000,000+
Protection level IP65
* Weight with minimum stroke
** Dimensions with minimum stroke
*** Lifetime at peak force
Voltage DA99-W2X DA78-35
230 VAC 400 VAC 230 VAC 400 VAC
Rated motor torque Nm (in-lb) 7.9 (69.9) 7.9 (69.9) 4 (35.4) 4 (35.4)
Speed @ bus voltage
RPM 3,000 3,000 3,000 3,000
Insulated thermal endurance class 155 (F) 155 (F)  155 (F) 155 (F)
Thermal switch temperature °C (°F) 130 (266) 130 (266) 130 (266) 130 (266)
Continuous current A 10.8 5.3 5.2 4
Peak current A 32.6 16 16.2 12.4


High force solution
DA99-W25, DA99-W212
Length A, mm (in) 320 (12.6)
Weight, kg (lb) 10.6 (23.4)

*DA99-W2X with 150 mm stroke and without mounting option

Ultra-Compact Form Factor Variant

For space constrained welding applications, Diakont offers DA78-35 electric servo actuators.

Length A, mm (in) 285.5 (11.2)
Weight, kg (lb) 6.7 (14.8)

*DA78-35 with 150 mm stroke and without mounting option

More info in Spot Welding Actuator Brochure

Performance And Lifetime

The automotive industry imposes strict requirements for actuator minimum service life of >10 million welding cycles. Rigorous testing has shown Diakont’s welding servo actuators consistently outperform other actuators of similar sizing in service lifetime, exceeding 16 million welding cycles up to a force of 22kN (4,946 lbf), and an impressive 30 million welding cycles at up to a force of 18kN (4,047 lbf).


Duty Cycle
The maximum force applied to the actuator during testing was 22 kN. The service lifetime tests were run using the following common welding industry duty cycle:
  • Welds per minute: 20
  • Duration of the welding cycle: 1.4 seconds
  • Duration under maximum load: 0.8 seconds
Mounting Options

To facilitate integration, Diakont actuators are available with standard and custom mounting options.

  • Extended tie-rods
  • Front flange
  • Rear clevis
  • Side mounting
Internal Radial Load Support/Anti-Rotation

The design of some weld guns (especially C-type) requires radial load support to maintain weld gun tip alignment and minimize harmful radial loads on the actuator shaft. To enhance radial load durability, Diakont provides an optional internal radial load support that also performs an anti-rotation function. This compact solution weights just 2 kg and adds 95.5 mm.

Maximum radial load durability
 With radial load support
 (for stroke 150 mm)
1,440 N (324 lbf)
 Without radial load support 540 N (121 lbf)

Electric Brake

A brake option is required for some types of robots. For these applications, Diakont offers a specialized compact brake solution that increases the weight of the actuator by only 1 kg and its length by 39 mm.

Electric brake specifications
 Maximum holding force for DA99-W25
2550 N
(573 lbf)
 Maximum holding force for DA99-W212
900 N
(202 lbf)
 Power supply voltage 24 VDC
 Input power 11 W



Manual Drive Options

To adjust the actuator in the case of sudden power loss, Diakont provides an optional compact manual drive. The manual operation port is located on the upper side of the actuator. Manual operation can be engaged, quickly and easily, by unscrewing the manual operation port, inserting the drive tool, and beginning drive tool rotation either manually or with a screw gun. Manual drive can also be provided using flats on the output shaft.

Water Diversion

Diakont electric actuators use specialized seals and water diversion channels to prevent ingress into the actuator internals.