Introducing pick-and-place robots to your assembly line

In this article, we’ll provide an introductory look at what you should consider if you’re looking to deploy robots on your factory floor. We hope this will help demystify the process for newcomers to automation and also serve as a handy reminder for those at a more advanced stage of their journey. Below, we’ll cover repetitive, well-structured pick-and-place applications since these are a typical first step.

Some pick-and-place tasks, like machine tending and palletizing, are specific enough to have specialized hardware and operator interfaces. Others, like part transfer and assembly, are simple enough that they can be built from scratch every time with modular hardware and intuitive code-free programming tools.
We’ll focus on the latter in this article, although the process generally applies to any robot pick-and-place application.

1. Gather specifications

Since you’ve already identified a process (pick-and-place), you’ll have ready access to most of the information needed. As a starting point, here are a few things to look out for when working with robots for pick-and-place:

• Part characteristics (weight, material, size, shape). Affects robot size and tooling type and design.
• Pick-to-place dimensions. Affects robot size.
• General dimensions and available space. Affects cell type.
• Speed, in parts-per-minute. Affects robot type and cell type with respect to safety.

2. Make assumptions

To narrow down the options, you’ll need to make some assumptions. Keep track of these, because if the end result does not meet your requirements, you’ll come back to this step to reevaluate your assumptions, make trade-offs, and iterate on your design.

Later, you’ll validate these assumptions through reach studies, partial or complete process simulations, and/or safety risk assessments. For now, it’s enough to think about whether you have any specific requirements to keep in mind while selecting your robot cell components.

Here are some common assumption types to get you started:

• Part flow to/from the cell
• Robot mounting location and orientation
• Acceptable safety and guarding

3. Select your cell configuration

Based on your process and the assumptions you just made, now’s the time to choose a robot cell configuration. This is closely tied to your application’s requirements for safe and appropriate human operability, which at this point are still assumptions.

Design is an iterative process, since certain outcomes can only become known once the entire system has been configured, so choose something based on your assumptions and don’t hesitate to come back to this stage with your new learnings.

Configuration	Example
Open concept with a power and force limitation
Open concept with speed and separation monitoring
Partially accessible with speed and separation monitoring
Fully enclosed with a safety-rated monitored stop

4. Select your robot

Robots come in many different types and sizes. You’ll want to consider:

• Power-and-force limited (collaborative) robots vs. traditional robots.
• Articulated vs. delta vs. SCARA robots.
• Payload capacity.
• Robot reach.
• Robot speed.
• Ease of programming.

To learn more, see this guide to the entire robot selection process: vention.io/blogs/four-considerations-for-purchasing-your-cobot

You can also shop robots on Vention online: vention.io/parts-library/category/robots

5. Select your robot base

The robot has to be physically supported by a rigid base that will not vibrate excessively at full-speed operation. There is a trade-off between system rigidity and cost, so you might decide to accept some vibration in the base and locate the part after placement using a more cost-effective system, like a pneumatic pusher.

However, since simple pick-and-place applications are not very demanding in terms of accuracy, you might not even need to worry about it. And if there are stringent requirements, you’ll probably need an external locating system anyway—whether mechanical, gravity-based, or vision-based—regardless of which base you choose.

Here are the most common robot mounting options:

• Pedestal
• Workstation
• Overhead
• Range extender (linear slide, vertical or horizontal)

Vention’s public design library is a great place to get inspiration:

• Pedestal & Bases
• Range Extenders
• Complete Pick-and-Place Cells

Plus, if you’re looking to start designing a pedestal from scratch, here’s a handy reference on stability: vention.io/resources/guides/calculating-the-stability-of-your-robot-base

6. Select your tooling

A robot without tooling is like an arm without a hand. Tooling refers to end-of-arm tooling (EOAT): the actuator that mounts on the flange at the end of the robot, and that directly interfaces with the parts.

There are two main classes of EOAT: pneumatic and electric. If you have easy access to compressed air, a pneumatic gripper is often more cost-effective and lighter than an electric one, leaving the robot with more payload capacity.

On the other hand, pneumatic grippers do not have force-limiting functions and can pose a real pinching hazard. That’s why electric grippers might be a better choice if your application is collaborative or power- and force-limited.

In any case, whether they’re actuated pneumatically or electrically, here are the main types of EOAT for pick-and-place applications.

	Type	Good for
	Underactuated	Larger parts. Larger min/max stroke range.
	Parallel 2-finger	Outside or inside gripping. Higher-speed applications.
	Parallel 3-finger	Cylindrical parts. Outside or inside gripping.
	Soft finger	Irregular part shapes. Soft packaging.
	Suction cup(s)	Flat surfaces (preferably non-porous material).
	Foam	Flat surfaces (preferably non-porous material). A larger range of part sizes and types, compared to suction cups. (The foam conforms to items and does not need to a tight seal, but it consumes more air than the cups do.)
	Magnetic	Ferromagnetic parts.

7. Consider safety

Safety is an essential part of any industrial robot cell. It’s rare for a production line to be completely “lights out”—without any human operation or interaction—so safety approaches must be carefully considered.

Safety selection is directly linked to robot cell configuration, which we’ve covered in step 3, so here we’ll take a closer look at each safeguarding method.

	Type	Good for
	Hard guarding	High-speed applications. Sharp-object applications.
	Light curtains	Small spaces, where there might not be room to add a wall. Maintaining ease-of-access (as opposed to doors or walls).
	Laser area scanners	Speed and separation monitoring for fenceless configurations, whereby the robot is made to slow-down or stop as a function of how close an operator is to the robot workspace.
	E-stop module	Always required in any automation project; often directly built-in on the teach pendant available from the robot manufacturer.

Important: None of these safeguarding devices are enough to guarantee cell safety. You must always conduct a proper risk assessment. You can’t sign off on a risk assessment until you have the actual physical machine, but it’s good practice to have an advanced draft during the design phase so you can mitigate potential risks through design changes. Below are the most relevant standards and reports for robot systems.

RIA number	Name	ISO Number
RIA TR R15.306	Task-Based Risk Assessment Methodology	ISO 12100
RIA R15.06	Industrial Robots and Robot Systems- Safety Requirements	ISO 10218-1 and ISO 10218-2
RIA TR R15.606	Technical Report - Industrial Robots And Robot Systems - Safety Requirements - Collaborative Robots	ISO/TS 15066
RIA TR R15.406	Safeguarding	ISO 13855

8. Validate

Before buying all the equipment, you’ll want to do some form of validation to make sure you’ll get the expected performance. Below are some typical tests and corresponding tools.

What to validate	Why? (To ensure that the…)	How (tool or method)
Structure	Structure will hold the load of the robot and its maximal forces.	Deflection calculator or full FEA (finite element analysis).
Robot reach	Robot has sufficient length to reach all the points it needs to.	MachineBuilder.
Gripper	End-of-arm tool can consistently grip all parts.	Physical test. (Although in most cases, you can get enough info from the gripper specs.)
Cycle time	Desired throughput in parts-per-minute will be reached.	MachineLogic, or offline programming tools offered by the robot’s manufacturer.
Safety	Robot cell meets all safety requirements.	Risk assessment (see step 7 above).

More info

As a handy reference for your first robot pick-and-place project, here’s a list of all the Vention resources we linked to above.