Q & A: Your Questions Answered

Design Engineering and Robert Bosch address some of the pressing issues of the day

Q: I am a process engineer and have been heavily involved in redesigning our production equipment. The majority of the new components are pneumatic and I am responsible for making sure all of the components are correctly installed and properly maintained. Are there any guidelines I should be following?

A: For hassle free operation it is essential that pneumatic controls are correctly installed and efficiently maintained. Although this can seem quite daunting to the inexperienced, there are a few easy steps you can follow to make the project as smooth as possible. The main points to note are:-

DESIGN

When drawing the circuit diagram make sure that all components can be easily traced and identified.

For ease of identification, label all of the components in the same manner as the circuit diagram.

To improve maintenance, fit service units as near as is practical to the point of use.

When designing the circuit, locate components so that they can not be easily damaged by falling parts or a person climbing on to the machine.

Install a filling valve (soft start unit) to help prevent cylinders making any sudden movements when air is applied to the system.

Protect exhaust ports from dirt, dust and water by facing the ports down and fitting silencers. Also use oil separators to protect the environment.

INSTALLATION

Always make sure that the air supply is sufficient for the application and not restricted. Common problems result from undersized or kinked hoses and restrictive fittings. Once complete; check that the system pressure does not drop by more than 1/2bar in operation.

Make sure all ports on components waiting to be fitted have covers or caps to prevent foreign particles entering.

All tubing and fittings require leak proof joints. If any thread lock or sealant is used only apply it to the male thread to minimise the possibility of any of the material being forced into the component.

Check that no dirt has collected on tube ends before fitting to the system.

Make sure that you mount any pneumatic cylinders securely to ensure that the piston rod can move freely through its full stroke.

Ensure that no undue side stress is placed on the piston rod to shorten the life expectancy or cause unnecessary cylinder wear.

In applications where the piston rod or machine component actuates signalling devices, ensure that the actuation is correct and no undue force is applied to the signalling element.

All brackets used for mounting cylinders and limit valves should have sufficient support and not flex during operation.

The best way to ensure that a system works properly and causes few problems is to devise a suitable installation and maintenance checklist. Because each operation and its environment are unique, maintenance schedules will need to reflect this. Use the points above and refer to your pneumatics supplier who should be familiar with your particular situation to help you do this.

Q: I work for an electronics business that AEs planning to install a conveyor system into its production process. I am unsure of what needs to be taken into account. Are there any design tips that you could give me?

A: Planning a conveyor system can be a complicated process and there are many technical, operational and performance criteria to take into account.

An aspect often overlooked is the DFMA or automation friendly nature of the product. The simpler the product is to assemble, in terms of the number of components and time at station requirements, the more cost effective a conveyor will be.

The most important operational aspect is the combined cycle time and production volume expected from the system. It is these values that will determine the financial feasibility of the conveyor.

Two aspects are of prime importance. First is the operational sequence which establishes the physical pallet routing and overall conveyor design. Next is matching the conveyor’s overall capabilities to the size and weight of the load.

Another major point is the reinvestment or reusability of the proposed solution. Product life cycles are decreasing rapidly, so having a conveyor system capable of simple future redeployment can have some very positive benefits.

A useful planning aid is software designed specifically to create a simulated layout in AutoCAD format, such as Tssoft from Bosch – which also allows simulation.