Building of a Delta mini G2s pro and problems encountered
Posted: Tue Dec 01, 2015 12:31 am
- first problem were with “Rod-end bearing holder” (part #3), it is more convenient to fix them to the “Diagonal Rod joint” before fixing this one to the carriage mount (error inthe building guide), but the major problem is that their thin part (of a 6mm diameter) is too long so it is impossible to fix securely the diagonal rod (part #4 ) on them. The length is just 0.3 mm too long but it makes the diagonal rod sliding on them even if you screw at the maximum the Round head screw. Because of this sliding the repeatability of the positioning is very poor, I do not understand why nobody noticed that before and complain If you supply new “Rod-end bearing holder” just half a millimeter shorter the printer will be much more efficient..
- The second problem is with the “Timing Belt” (part #36), It is 5 millimeter thick and we must put a 3mm screw in it (not a big margin each side), so at least (for now ) in one case i make a hole not exactly in the middle and when I stretch it, it tears apart. I will need to change it but you clearly should supply at least on meter more to cope with this kind of problems.
- Third problem is with the “hot-end fan”. I received a two wire fan and the building guide show a picture of a 3 wires connector in the step 3 of chapter 6. So where do I connect my two wire connector ?
- Last thing; the building instruction guide ends with this sentence “(we should verify that) Current for stepper motors is set to the correct level “. But nowhere there is any idea on how to do that. So I suppose we have to monitor each A4988 carrier to verify if their current limitation is consistent with the step motors we have even if no indication of their type is given in the documentation ?
My guess is that the 3 axes motors are NEMA 17 42SHD0217-24B (they are supposed to have 2.5 ohm per phase and i measure 2.2) so their maximum current should be 1.5 A.
The two extruders motors are HYBRID stepper motor 42HSC8402-25B with also a maximum current of 1.5A. The current limitation in the A4988 modules should be set at 1.5 / 0.7 = 2.1A (saying that the maximum current of the circuit is 2A) , so the Vref of each module should be 2.1A / 2.5 = 0,856 V (ref https://www.pololu.com/product/1182) . Am I right ?
I measured voltage between 0.805 and 0.873
- 5) I had many problems of connection at the beginning. In fact the USB cable you sent me was faulty. I took another one and the connection is now perfect.
- 6) For the first tries of printing I noticed that my PLA was beginning to melt at a temperature of 178°. It could not be true. So the thermistors are the one declared in Marlin. Where could I found the correct tables ?
- The second problem is with the “Timing Belt” (part #36), It is 5 millimeter thick and we must put a 3mm screw in it (not a big margin each side), so at least (for now ) in one case i make a hole not exactly in the middle and when I stretch it, it tears apart. I will need to change it but you clearly should supply at least on meter more to cope with this kind of problems.
- Third problem is with the “hot-end fan”. I received a two wire fan and the building guide show a picture of a 3 wires connector in the step 3 of chapter 6. So where do I connect my two wire connector ?
- Last thing; the building instruction guide ends with this sentence “(we should verify that) Current for stepper motors is set to the correct level “. But nowhere there is any idea on how to do that. So I suppose we have to monitor each A4988 carrier to verify if their current limitation is consistent with the step motors we have even if no indication of their type is given in the documentation ?
My guess is that the 3 axes motors are NEMA 17 42SHD0217-24B (they are supposed to have 2.5 ohm per phase and i measure 2.2) so their maximum current should be 1.5 A.
The two extruders motors are HYBRID stepper motor 42HSC8402-25B with also a maximum current of 1.5A. The current limitation in the A4988 modules should be set at 1.5 / 0.7 = 2.1A (saying that the maximum current of the circuit is 2A) , so the Vref of each module should be 2.1A / 2.5 = 0,856 V (ref https://www.pololu.com/product/1182) . Am I right ?
I measured voltage between 0.805 and 0.873
- 5) I had many problems of connection at the beginning. In fact the USB cable you sent me was faulty. I took another one and the connection is now perfect.
- 6) For the first tries of printing I noticed that my PLA was beginning to melt at a temperature of 178°. It could not be true. So the thermistors are the one declared in Marlin. Where could I found the correct tables ?