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Smooth International Group Limited

Smooth motion solutions, specialized in stepper motor, linear stepper motor, can-stack linear actuator in a wide and huge range series products since 1994, highly recognized as the leading manufacturer of linear motion solution.
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The following are the most frequently common asked questions

 If you have a question that is not on the list, please feel free to contact us we will answer your question within 2 hours. 

Q1: What ‘s the convert relationship between mN.m and N.m,, oz-in?
1Kg=1000g    1kg=9.8N  1m=2500px  1N=1000mN  1 in=25.4mm  1b=0Z  1B=1N

Q2: Could you tell me the difference between the full step and half step of stepper motor or linear actuator?

If 1.8 degree motor,when motor rotate one round is 360°,360°÷1.8°=200,this means that the motor will do 200 steps per rotation.If 0.9 degree motor,when motor rotate one round 360°,360°÷0.9°=400,the motor will do 400 steps per rotation200 steps means half step,400 means full step.

Q3: What is the performance difference between unipolar and bipolar wired motors?

The bipolar will have abount 30% more torque and force than of the unipolar unit per given input  powter.Bipolar is typically the motor of choice.

Q4: What is the difference between a 4 wire and 6 wire stepper motor?

The 4 wire motor is a "bipolar" which means two coils. In its operation two coils are on at any given time and current is reversed in the coils to achieve rotation. The 6 wire motor is a "unipolar" device with four coils with the comments are tied together in each phase and brought out.

Q5:  Explain the difference between the Captive, Non-captive and External linear actuators?

The Captive actuator has a built in anti-rotation mechanism through the use of a splined output shaft that allows it to extend and retract as unit with no requirements for additional anti-roatation.The captive actuator is designed for shorter strokes.
The Non-captive actuator has a lead screw going through the motor and has no reasonable stroke limits but must be attached to an assembly that will not rotate. This will then allow the lead screw to extend and retract without rotating.
The External actuator uses a lead screw and nut combination that extends out from the motor.Linear motion is created by the nut traversing back and forth as the lead screw turns.

Q6: Could you explain the Pitch,screw lead,and resolution of the lead screw for me?

Screw lead ÷ Pitch=the heads of the thread. resolution×200=screw lead.

Q7: How much life can I expect from the assemblies?

For anti-backlash nuts, life is generally defined as the ability for the nut to compensate for wear.Otherwise, on a general purpose nut, its defined by the amount of wear that can be tolerated before the nut can not hold the intended loas or the clearance that develops is objectionable for the accuracy of the system. Life can be improved by the different nut styles we offer.

Q8: What material are the leadscrews and buts made from?

Generally, the screws are rolled from 303 stainless and the nuts are made from self-lubricating polyacetal. Other materials are available on a custom basis. For screwa we have used 316 stainless, aluminum and stell. For nuts we used our Kerkite material, PEEK, Ertalyte, and other custom materials to meet various environment and performance considerations.

Q9: What is the minimum and max gear ratio on the gear stepper motors?

The minimum one is 1:5, the Max one is 1:200.

Q10: Could you kindly tell me pulley MXL, XL?

MXL: qty of teeth ·2.032=3.14/circumference = diameter
XL: qty of teeth ·5.08=3.14/circumference = diameter

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