What Can You Do With a SCARA Robot?

Do you need a SCARA or another type of robot? With a new SCARA added to our Robot Library, here are the benefits of this classic robot.

In one of our recent updates to RoboDK, we added support to a new collaborative SCARA robot: the Dobot M1 This means that, at time of writing, we now support 35 SCARA models from 11 manufacturers.

But, what are SCARA robots?

What are the benefits of them over the more common 6-axis robots?

As the performance of 6-axis robots continues to improve year after year, you might be wondering: Do I need a SCARA?

Let’s take a look at this classic robot and find out what you can do with it.

What Does SCARA Stand For?

The SCARA was invented in 1978 by Professor Hiroshi Makino at Yamanashi University in Japan. The robots were designed for assembly applications and they have been used in industrial assembly lines since 1981.

SCARA is an acronym, but the meaning of the first letter A has changed slightly over the years.

The two definitions are:

  1. Selective Compliance Assembly Robot Arm — This was the original definition and is still probably the most common.
  2. Selective Compliance Articulated Robot Arm — This definition came into use later as SCARAs have been applied to other tasks which do not involve assembly.

These days, SCARAs are used for a whole host of different industrial tasks in a wide range of industries.

What do those other terms mean?

The final two letters (RA for “Robot Arm”) are self-explanatory, but what about Selective Compliance?

Selective Compliance

In robotics, compliance means that a robot has flexibility in one or more of its joints (or sometimes in its mechanical structure). If you push a compliant robot, it will give way under your touch. It won’t push back or hold steady.

SCARAs are compliant in the X-Y axis but rigid in the Z-axis. This gives them some flexibility which is particularly useful for assembly applications which require compliance— e.g. inserting a peg in a hole.

How a SCARA Compares to Other Robots

These days, there are so many different robots with different levels of performance. It is difficult to say that SCARAs are “better” than other types in any particular aspect. There is often more variability between individual robot models than between robot types.

Even so, here are six categories where SCARAs tend to be different from other robot types.

Rigidity

Due to their selective compliance, SCARAs are less rigid than Cartesian or gantry robots. However, they are more rigid than both 6-axis robots and Delta robots due to their rigid Z-axis.

This makes SCARAs a kind of “halfway house” between Cartesian and 6-axis robots.

Speed

SCARAs are very well suited to high-speed assembly applications. They are generally faster than 6-axis robots. As a result, it is much more likely to see them being used for pick-and-place. However, they are not as fast as Delta robots which are the top choice for high-speed pick-and-place.

Axes

One of the clearest distinctions between SCARAs and 6-axis robots is that they have fewer Degrees-of-Freedom. Like most Delta robots, they have only 4 axes.

Payload

The payload of SCARAs is generally quite low. The models in our Robot Library can lift between 0.5-20 kg. This is much less than 6-axis robots which can lift between 1-1700 kg, but it is more than Delta robots which can lift between 0.3-8 kg.

Repeatability

Assembly tasks require quite a high degree of precision, which means that SCARAs generally have better repeatability than other types of robot. The robots with the best repeatability in our Robot Library are all SCARAs and it’s not uncommon to see them with a repeatability of just 0.01 mm.

Cost

When SCARAs were first introduced in the 1980s, they represented the best price to performance ratio for high-speed tasks. This is still true today as they tend to be cheaper than the faster Delta robots.

5 Tasks That SCARA Robots Excels At

Robots are very adaptable and almost every type of robot can be used for a variety of tasks. SCARAs are no different but there are some tasks that they really excel at. Here are five of them:

1. Small Assembly

The task that the SCARA was designed to do. High-speed assembly tasks, such as those in the electronics industry, are very common for SCARA robots. Their selective compliance means that they can perform insertions more easily than other types of robot, without having to use complex programming.

2. Pick and Place

Image courtesy of Staubli

SCARAs are often the quickest, cheapest robot for high-speed pick and place. Their speed is only beaten by Delta robots, but they are usually easier to install because they do not require the robot to be mounted above the workspace.

3. Laser Engraving

SCARA robot drawing application

The high precision of SCARAs means that they are also very well suited to laser engraving and drawing tasks. Over the last few years, several end effectors have come onto the market which allow you to add laser engraving capabilities to any small robot.

4. 3D Printing

Another task which is becoming a rising star in the world of robotics is 3D printing. We’ve already seen a lot of applications where 6-axis robots are making it possible to print much bigger objects with 3D printing technology. SCARAs are well suited to this new application on the smaller end of the scale.

5. Soldering

SCARAs are very popular in the electronics industry because they can be used for many of the core manufacturing tasks. One such task is soldering. With a suitable end effector, they can provide very consistent quality of solder and improve efficiency when compared to soldering by hand.

How to Pick the Best SCARA Robot for You

If you think that a SCARA robot could be the answer to your problems, you can try one out for yourself immediately.

Just download a trial copy of RoboDK. Then, download a SCARA models from our Robot Library (choose “Scara” in the “type” filter menu).

We have SCARA models from all of these robot brands: Adept, Denso, Dobot, Epson, KUKA, Kawasaki, MCI, Motoman, Precise, Staubli, Toshiba, and Yamaha

You can then easily test out your application in the simulated environment before you decide to invest in the robot itself.

How could a SCARA be useful in your business? Tell us in the comments below or join the discussion on LinkedIn, Twitter, Facebook, Instagram or in the RoboDK Forum.

Alex Owen-Hill

About Alex Owen-Hill

Alex Owen-Hill is a freelance writer and public speaker who blogs about a large range of topics, including science, presentation skills at CreateClarifyArticulate.com, storytelling and (of course) robotics. He completed a PhD in Telerobotics from Universidad Politecnica de Madrid as part of the PURESAFE project, in collaboration with CERN. As a recovering academic, he maintains a firm foot in the robotics world by blogging about industrial robotics.

View all posts by Alex Owen-Hill

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