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MaL

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Posts posted by MaL

    Redundancy in larger models?

    in All Things Model Flying

    Posted

    Two Batteries and two switches here. The simple addition of a diode or a bridge rectifier in each battery line between the battery and the switch removes any possibility of a duff cell pulling the other good battery down. Common the two sides of the slide switches to reduce the possibility of a switch failure. Using Li-Fe batteries allows for the forward voltage drop across the diodes and supplies the Rx with just under 6v. Use diode/bridge rectifiers commensurate with the expected loads. If you don't need to drop so much just substitute single diodes for the bridge rectifiers

    Test each battery supply individually at switch on and switch off..its pretty obvious if you have a duff cell in a pack. follow this regime and there is not much that can cause a catastrophic power failure.

    Anet A8

    in 3D Printing

    Posted

    The extruder cooling fan must remain on, blowing air over the extruder heatsink while the hotend is hot. Most , if not all, controller boards automatically switch it on and off according to the thermistor temperature. Failure to keep  the 'cold end' cool will cause the filament to melt too high up in the nozzle and cause a jam - usually referred to as heat creep.

    The filament cooling fan is controllable via the software and is usually switched on after the first layer has been deposited to assist maintaining the print integrity when printing overhangs and bridges, it 'sets' the plastic before it can droop. It is only needed if you have overhangs.

    Edited By MaL on 06/06/2017 10:36:39

    Anet A8

    in 3D Printing

    Posted

    For getting the bed levelled I suggest you go get one of these - **LINK** and print yourself a holder that attaches to your x carriage. You can adjust any discrepancy in the X carriage to bed parallelism by moving the Z axis leadscrews against each other. Adjusting the Y axis will require some form of adjustment screw... I assume the A8 has one. It really is quite simple to get the bed level once you can see the dial gauge indicating which way it is sloping. Once the bed is as level as it can be (neither glass nor machine plate is perfectly flat) your probe can set the print height.

    Anet A8

    in 3D Printing

    Posted

    Trying to understand exactly what the probe is doing..

    Is it making a map of 9 sample bed heights during a probe and amending Z=0 as it is printing (so the head moves up and down during each layer as well as the head moving up at the end of each layer, as per a delta machine

    or

    the probe just decides the average head height (allowing for x,y and z offsets) from taking 9 readings from different places on the bed during the probe and calls that Z=0

    I guess it is most probably the latter. If so the probe is not helping you at all in levelling the bed, just in setting the first layer height. This is a task I usually do on the fly, if it is needed, while it is laying down a perimeter skirt to get an even 'squish' before it starts the actual print.

    Anet A8

    in 3D Printing

    Posted

    I'm curious Geoff, how does the proximity sensor make such a difference?

    I would understand it on a delta printer as all three stepper motors have to turn as the head traverses the plate so the electronics can compensate for height variances 'on the fly', but on a cartesian printer the z axis only moves at layer change. also because the electronics have to calculate each and every head movement any inaccuracies in the mechanical build will create errors - which don't occur with 3 discrete axes. I assume the printer now does a mesh levelling probe before each print now? Does your z height now move between layer changes with the sensor?

    Once you have levelled the plate against the x and y axis height adjustment is quite simple to achieve the required first layer height within the flatness of the plate. If your plate is more than10 microns or so out of true flat then you are going to have problems with or without a proximity sensor

    I do have a delta printer, along with a couple of cartesians, the delta needs some form of height sensor (in my case it is a piezo sensor), but in my experience the cartesians, once set up (I use a dial gauge in a printed holder), are no bother getting the first layer right

    Cura 2.5.0

    in 3D Printing

    Posted

    Only got an older version of Cura here (2.3.1) but when importing a file to process it comes up with a raft that can be removed by unticking" Helper Parts: Print Build Plate Adhesion" (as Og says). It is half way down the display on the right hand side. It is usually helpful to set the adhesion parameter to a skirt to prime the extruder before printing the piece unless you think you will need more material on the build plate to keep the item in place during printing, in which case you might try brim or raft.

    Having said all that it doesn't look like a raft to me.....the support structures normally follow the contour of the item being printedfrown

    Somewhere to share our own 3D designs

    in 3D Printing

    Posted

    It will certainly be heavier and less versatile than balsa for production of a flying model at this scale. I printed the 5 cylinder radial on thingverse a while ago (https://www.thingiverse.com/thing:52769) and I fancied having a go at printing something else that I thought would be a nice display piece. If you are thinking of producing an actual flying 3d printed model I would suggest the guys at 3dlabprint.com would be a good place to start....I'm contemplating buying their Stearman, just printing out the test piece as I type smiley

    The cost of the pla would be insignificant..less than 50p.

    Somewhere to share our own 3D designs

    in 3D Printing

    Posted

    Hi Colin, I wanted the exercise in using the design software with the intention of printing the formers and using balsa for the stringers, covering with tissue and dope but I now think it would be better to print the stringers too and leave it as just the framework without a covering - perhaps other designs later as well....

    formers printed..

    Wings.....

    An early trial...

    Aerofred is a great resource for plans isn't it!!

    2.4 interference from FPV?

    in General Electric Flight Chat

    Posted

    There is a thread on singlechannellersreunited about a 2.4Ghz handheld band scanner. It uses an arduino nano, an nRF24L01 board and an oled display.

    All the construction details are in this thread.... **LINK**

    Total cost about $15 and it works very well indeed, but it can only show you signal strength where it is....not 200 ft up!!

     

    Edited By MaL on 29/05/2017 12:26:45

    Soldering Iron Recommendation please

    in Gadgets and Electronics

    Posted

    IMHO soft lead soldering U/C legs is a bit weak, better off soft silver soldering them with a torch. They use un-regulated torches here in France - like this one 

    just screw the feed pipe onto a butane bottle and use silver solder like this -

    you can always use the torch to start your barbeque as well!!

     

    Edited By MaL on 21/05/2017 17:14:31

    Is this a scam

    in Chit-chat

    Posted

    Recently had an email purporting to be from Paypal advising me that they had restricted access due to unusual activity and inviting me to log on and assist them in sorting it out, no links given in the email by the way.. so I logged in manually and straight away got a page informing me that the account was locked and I had to send a scan of some personal details...now the warning bells are tingling in my head... but I had manually logged on and the URL was the correct address.. so I uploaded the requested copy. Next day I had another email advising me that unfortunately the account was to remain locked but perhaps I would like to change my password (again) and then login and request help through the secure email within the site.....unfortunately the account was locked... i.e. NO access, so I rang the help line and eventually got to talk to a rep who was able to re-open the account for me.. the reason it was locked??------

    For three years I have used, pretty exclusively, a VPN - to protect my computer from unwanted contact... and use of a VPN is apparently verbotten with Paypal!....only took them 3 years to discover my non-compliance with their ToC's. So now, no VPN use with Paypal and I will have to put up with them giving me the French language on their site as my true IP address will flag me up as being in France, even though I have stipulated English language in my account preferences...angry 2....

    The moral of this story is........Not all the emails or phone calls are scams...but you need to exercise care with all unsolicited emails.

    Anet A8

    in 3D Printing

    Posted

    I wasn't referring to the stepper motors Geoff, I meant the stepper drivers on the circuit board. Heat can be an issue on some boards as the drivers could be passing a couple of Amps each. There are certainly examples of people having these A8 boards just fail and I was wondering that as some other builds have flushing fans to move air over the electronics to remove excess heat if it would not be a good idea to add a fan, especially if you are going to enclose the board.

    If you are doing frequent bed levelings then you have something loose as Tony says... I have used fuel tube in the past instead of springs and substituted captive nuts for their longer thread length on the levelling mechanism.I You can also gain another 5mm in build height capability by lowering the bed with shorter lengths of fuel tube. ! rarely have to level the bed, usually only if the z steppers have got out of sync somehow..face 5

    Strange Win 10 PC problem

    in Chit-chat

    Posted

    Try setting up a new user account to see if your problem is account related.. from task manager - new task - type control and then you can access the users control panel (on win7 at least) , set up a new admin account and reboot and try logging on with the new account.

    Simplify 3D

    in 3D Printing

    Posted

    That, along with the software only connecting to Flashforge printers, will be so you can only use the software if you have purchased one of their printers...which is fair enough... Perhaps someone with one of these printers could answer a question...

    Is there an option to append additional gcode to the sliced file once you have connected a printer? This is IMHO a requirement as it allows you to amend the printers behaviour pre and post printing.

    Mystery kits from Leicestershire 1980s

    in Traditional kits

    Posted

    I remember the kits - or rather I remember the sale of the kits, there was a Super60 type kit, conventional build, and a 40/60 sized sports type that had a G/F fuz IIRC, and a .25 sized sports conventional build.... there was also a glider, can't for the life of me remember the name but I seem to recall it was a short name...4 or 5 letters...grrrrrr...nope...sorry....too much has intervened!!!

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