Thursday, 18 August 2016

3D Printing PLA Not Sticking

I have found that using blue masking tape works for helping adhesion of PLA on heated build plate. Though the brand I bought was not very good in that the print wouldn't stick to the plate. 3M blue masking tape is apparently the best for this. While I waited for this tape to arrive I used hairspray sprayed onto the glass build plate , this provided good adhesion for my prints. I like the idea of the blue tape as it's less messy than the hairspray method. 

CTC Replicator 1 (Dual) Clone RFI problems

Occasionally the display on this printer becomes garbled and the reset has to be pressed. I also noticed that when this printer is on it affects the speed of my fibre to the cabinet FTTC broadband. As a licensed Radio Ham I did notice that there was little or no RFI (Radio Frequency Interference) filtering at the mains input or any ferrite sleeves over wires going to the motors and thermocouples etc. I think that the switchmode power supply is probably causing RFI to be transmitted along the mains and then it's being picked up by the telephone line so reducing the broadband speed. I will retrofit filters and ferrite's to reduce the noise made by this machine. The graph below shows the slowing effect of this printer on my broadband speed.
I have since moved my printer to another room away from the telephone line until I get it filtered better.
WARNING! modifications to your machine may damage it or cause a FIRE! you have been warned. Be CAREFUL with Hot things like your printer!

CTC Replicator 1 (Dual) Clone Printing Issues Still!

I continued to have printing issues and it took me a while to solve. I found that the filament drive stepper was clicking all of the time and had got worse over time. I had disassembled the hot-end many times but nothing seemed to help. I then compared the hot-end channel 1 with channel 0 and noticed that the heater block was loose on the hot-end feed tube on channel 0. This meant that the block was heating up ok and the temperature was reasonably accurate but the heat transfer to the hot-end was very poor. This resulted in me having to turn up the heat to around 250 DegC to get any amount of flow from the nozzle. So I tightened the feed tube onto the heat block and re-assembled everything , immediately it began to print like new again. I was able to back off the digipot values to 118 from 122 on the printer settings and no feed clicking was evident during extrusion. Happy days!
 WARNING! modifications to your machine may damage it or cause a FIRE! you have been warned. Be CAREFUL with Hot things like your printer!

Friday, 12 August 2016

CTC Replicator 1 (Dual) Clone Extruder Clicking

My CTC Replicator 1 Clone (dual extruder) which I had for a good while and had done some really nice prints , then eventually I couldn't print anything. It would feed filament in a stop start fashion usually ending in a big bundle of filament. The symptom was the right extruder stepper drive just clicked when trying to drive filament though the hot end. I dismantled the 0.4mm nozzle and heat tube and found no blockages. I then set the extruder in motion heated but without the nozzle and it was still clicking while driving. It just seemed that the stepper motor didn't have enough torque to drive the filament. I looked around the interweb and there were mentions of digipots for controlling the drive current. So I connected my laptop via USB to my 3D printer and fired up the Makerbot Desktop software and  looked at the digipot settings under Devices -> Device Settings , the setting for digipot A was 118 so I increased this to 122 ,  the maximum is 127. While I was there I changed the setting for channel B to 122 as well just in case its stepper drive had the same problem. I tried driving the filament again but nothing changed click , click , clicking Hmmm! I then pressed the reset button and this time when I drove the filament stepper there was no clicking ,  result! It appears that any changes made to the Device settings are only read in on boot so even if you change something the old value is still used until you press the system reset button whereby the settings are read in from the eeprom.
WARNING! modifications to your machine may damage it or cause a FIRE! you have been warned. Be CAREFUL with Hot things like your printer!

Friday, 5 August 2016

Makerbot on OS X Stuck in Fullscreen Mode!

I have had trouble with OS X El Capitan Version 10.11.6  and Makerbot Version 3.9.1.1143. Once you have entered fullscreen on Makerbot you will not be able to go back to the windowed version using any of the standard key combinations like esc and the ctrl + cmd + F key , it will just plain not work. To fix this from the terminal , first create a copy of /Users/your_username/.config/MakerBot/MakerWare.ini something like MakerWare.ini.orig , then edit the MakerWare.ini file using vim and look for  the WindowGeometry="..........." entry. If you remove the data after the = including the quotes " and replace it with default ( it should look like this WindowGeometry=default). Then save it , when you start Makerbot it should start back in windowed mode - hooray!!! I took ages to find out how to fix this , even forums acknowledged it was a problem but gave no solution , the fix worked , go me!

Monday, 18 May 2015

Poor Man's Through-Hole PCB Rivet

First of all I have to thank Retromaster for his descriptions on how to do through-hole contact riveting. My double-sided prototype PCBs are done on a CNC Router but originally I was using just flexible wire soldered on both sides of the PCB. This method I found just created big solder bumps , not much good for surface mount IC's with through-hole contacts directly under them. So to remedy this situation I used a drill press with a 3mm stainless rod mounted in the Chuck. I put short pieces (approx 2.6mm long = thickness of PCB 1.6mm + Protrusion on each side of PCB 0.5mm X 2  ) of tinned copper wire whose diameter  matches closely the diameter of the via hole into the via for the through-hole connection. I positioned the 3mm rod in the chuck over the via to be riveted with the copper wire in the hole and gently rotated the drill press capstan. This pressed the copper wire into the hole. I relaxed the pressure on the PCB to allow the balancing of the head size of the rivet on both sides of the PCB. Below is a photo of some practice rivets and one via not riveted on a scrap PCB for practice, these rivets will have a light soldering using solder paste to ensure a good electrical connection. I am very pleased with this method of connecting vias on PCB prototypes.

Riveted through-hole connections


Thursday, 5 March 2015

BT Infinity and my HG612 VDSL2 Modem Firmware Upgrade

Speed kbps
My Home Download Speed
Warning: If you attempt what I describe here you may reduce your modem's usability to that of a brick , remember you are in charge of your own destiny. Note: I have two modems one for experiments and the other as backup.
 
I have been in the habit of using a Raspberry PI to log my ADSL2+ then VDSL2 speeds for a while now. The graph above is the speed of my ADSL2+ until I got BT Infinity or FTTC (Fibre To The Cabinet) , the time is about a year in span and speed is in kbps. Point A is when my ADSL2+ speed a took a dive due to a tree wearing through my overhead telephone line. It took BT about a full month to fix the fault and remove the subsequent speed cap at Point B , it took two emails to the BT Community Forum to get them to remove the cap even though they said that it had been removed , it hadn't.
Between Point B and C you can see my speed was unstable with my router continually dropping connection and then re-syncing at different speeds. You can see how unstable it was even after the line repair compared with the lead up to Point A , perfect. I then had BT Infinity installed at Point C using a BT Openreach Huawei EchoLife HG612 modem with unlocked firmware. This allowed me to log speeds , it isn't something that is enabled by default with BT's stock modem.
Between Points C and D it is not very stable speed wise , I have a long wire to the cabinet hence the lower than anticipated VDSL2 speed. So eventually I got a bit fed up with the variability of the connection speed so I tried new firmware in my modem , this firmware has a newer binary blob driver for the Broadcom modem chipset. Point D shows the time the modem had the new firmware flashed , it is a higher speed and also very stable , fantastic. So the only thing that has changed is the firmware change on the HG612 at point D. This also just shows that the digital signal processing elements have been improved in this binary blob driver.  Now I'm very impressed with the latest firmware for this modem , but it's a shame I've had to do all this firmware upgrade myself and that BT don't seem to be continually improving their modem firmware. This even though they do have BTAgent enabled to update firmware themselves.
I have BTAgent disabled because I don't want them to disable my logging system with their new firmware. They seem more concerned with not allowing their customers to actually see how bad their broadband connections are by disabling useful functionality. It has been noted by others that some of the BT firmware updates rolled out via BTAgent have disabled Web Configuration and telnet access to these modems.
Hope this helps you.