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FREE Fluid Power schematic design software

Article Updates:

Aug 31, 2019. Since Comotrol is part of Danfoss, Comatrol Easyvalve is not available anymore, so info about this software was removed.
Sep 25, 2019. URLs were updated in this post.
Dec 29, 2019. Info about QCAD was replaced with LibreCAD.
Oct 14, 2020. Info about nanoCAD has been added.
Oct 24, 2021. Info about Dassault Systemes DraftSight has been removed since there no free versions of DraftSight anymore.

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For my work I use AutoCAD LT or ePlan Fluid to draw hydraulic, pneumatic, lube and P&ID schematics. Companies where I worked and where I have the work now, provide this software because the price of them is unbelievably high for the regular individual.

One day, after reading of this article I decided to try to find something absolutely FREE for Fluid Power schematic design.

All software what I found, I divided into three categories:

  1. FREE Generic 2D CAD software
  2. FREE specialized Fluid Power design software for PC
  3. FREE specialized online Fluid Power design software

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Open/Closed center circuits

Summary:

  • Open/Closed center circuits – what does it mean?
  • Which one I use?
  • What can happen if I connect my system to wrong center circuit?

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There are two types of valve circuits can be used to control your system: “Open center circuit” and “Close center circuit”.

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New QuickDesign with SmartConnect from SUN

New QuickDesign with SmartConnect from SUN

New QuickDesign with SmartConnect from SUN

SUN announced about new SmartConnect schematic tool for manifold design.

The direct link where you can read more about this online application is here . In addition SUN offers the free webinars how to use it.

This is a very interesting feature which really simplifies the preparing work of manifold design. The online application is free and required a free registration only. Before this time it was a pretty complicate algorithm to indicate connections between cartridges’ ports. Now you just draw a hydraulic schematic (easy drag and drop SUN components) and with next step you get ready to use manifold design drawing set.

I used SUN manifold design before and tried to use it now with SmartConnect – I see the difference, and it is really improving and great feature.

I think the next step from SUN to be components’ placement optimization. I really like the idea of free online manifold design, but on the other hand, I found the complicated design from SUN has not optimal components placement and always manual correction required. And the problem with it – it hard to do in CREO because at the end we get STEP file which impossible (or very hard and uncomfortable) to modify. But anyways, this online application can give you some idea how to place components in the space and this is a good basis for your own manifold design. This is why I at least recommend to pay attention to QuickDesign with SmartConnect tool.

Proportional valve control calculation. Part 1.

Part 1. Proportional control of double acting hydraulic cylinder.

See also:
Part 2. Proportional control in the regeneration mode
Online calculator for cylinder proportional control.

Fig.1. Double acting cylinder control.

Fig.1. Double acting cylinder control.

The goal of this calculation is a definition of a cylinder velocity at any percent of the operating control signal at the valve’s solenoid (voltage or amperage).
For calculations we need to know: cylinder and valve parameters (take them from manufacturer catalog), values of forces at the cylinder rod (load), and pressure drop at the return line (can be assumed as zero if unknown).

Summary:
1.1. Hydraulic cylinder extension calculation.
1.1.1. Spool lands ratio.
1.1.2. Pressure drops at the spool lands
1.1.3. Balance of forces at the cylinder.
1.1.4. System pressure calculation.
1.1.5. Flow through spool lands: max. and at current voltage.
1.2. Hydraulic cylinder retraction calculation.
1.3. Full stroke time calculation.

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