We have defined 3 different quality standards for our robolink D joints and I want to explain the background of this issue. The 3 qualities are:
- “low cost”,
- “high end”
The main performance differences are stiffness, friction, precision (reverse play) and on the other hand cost. For size -20 and -30, the price difference between low cost and high end is ~factor 2, for size -50 it is ~factor 1,5. standard version ~ in the middle.
The high end version contains of our lubrication free worm gear with worm wheel made of iglidur J and worm shaft made of aluminum (hard anodized), it has ball bearings for the axial shaft load and for the back side (only version 102). The outer bearings are our PRT-01-xx (= high end rotary table made of aluminum with sliding elements made of iglidur J). Housing and inner connection parts are made of moulded plastic parts (our RN33), screws and nuts are stainless steel.
Most parts of the standard version are the same, but the back side has a sliding bearing (iglidur J) instead of the ball bearing (only version 102) and the PRT itsself is version PRT-02-xx-AL, which is a low cost version of PRT-01-xx. It has more plastic parts and thus is much lighter. Compared with PRT-01 is is a bit less stiff and a bit less precise. In a performanmce comparison of the to joints, we see no big differences for most applicaations as long as we do not get to the limits.
The low cost version of our RL-D in comparison contains a moulded plastic worm shaft and sliding axial bearings instead of the ball bearings. Also the PRT is not build with an aluminum outer ring but a moulded plastic outer ring (PRT-02-xx-LC). Friction is higher and precision worse than our “standard” version. It should be used only for “easy applications” as for example hand adjustments.
For size -20 and -30, all versions are available. For size -50, only version “high end” is available, as PRT-02-50 is yet under construction. We will have it in ~OCT 2015.
This new 16 page brochure tells the story and current state of the robolink development at igus. It contains some technical informations and describes the possibilities of our joint kit system, it is not a replacement of our catalogue, that you can still find in the “Support & service” section.
EN_robolink-Info_web.pdf (1.11 mb)
We have renewed the FAQ section (currently in German, English/international will follow soon)! Link to the german FAQ site:
Next steps will be:
Update the download area, including step files for our “new” joints, update the different joint arms with the “new” joints, new catalogue (planned for April 2014 / HMI trade show). AT HMI we will also present a totally new joint concept besides the existing one. Be curious!
Some words about grippers in combination with our robolink joint arms:
Different grippers can be attached to our arm tubes. One common solution are pneumatic grippers. They are (often) lightweight and not so expansive. We can adapt several grippers from SCHUNK, FESTO, GIMATIC, FIPA and others easily. Please ask us. Also suction systems are (usually) no problem for us.
But often pneumatics are not possible to be used (for example in mobile robots). In that case, we have the choice between electrical grippers or our robolink wire driven gripper. The igus gripper can not be adapted to 4 or 5 DOF arms because of 2 reasons: 1) the leading of the wire through multiple joints causes friction, as the gripper is spring loaded, the spring may not be sufficient in strength to close the gripper properly. 2) the aditional bowden cable can not be leaded through the lower joint because of space restriction. The igus gripper may thus be combined only with 2 or 3 DOF arms. We are workink on a better solution in this case.
My favorite product in the moment for the combination with our system is the electrical gripper by GIMATIC called MPPM 1606 (2 jaws) or MPTM 1606 (3 jaws). It is lightweight and really easy to control. Datasheets in ENG/IT and DE/FR are attached. We can adapt the grippers and also lead the electrical cable through any of our arms. Please ask us in case of interest!