Friday, 24 July 2009

The world in a box

I've been checking all my electronics purchases. The RS parts don't come labelled either - glad I didn't order much from them. The Farnell parts are all labelled with country of origin - this is a real multinational supply. I have parts from China (expected), Taiwan (ditto), France, Ireland, Thailand, Mexico, Japan, the Philippines, Austria, the US, and the ribbon cable seems to be the only part from the UK! Wow.

Do I need a tool for the ribbon cable?

Thursday, 23 July 2009

The order of things

I ordered from Farnell and RapidOnline the day before yesterday. Then I went off to Maplin by bus to get their parts.
Unfortunately, it is apparently Maplin's company policy to stock only 2 of the green LEDs. Be aware of this. It means it's better to buy a bag of 5 from RS instead, if you want more than 2 from a shop. As it is, I ended up taking what they had, and then discovering that fact when I got back home, so then I ordered from RS as well, meaning I'm going to have 7 green LEDs! I was planning to collect the RS parts from their local trade counter today - more later.

Here is a picture of the parcel of electronics components I collected from Maplin.
No I've not a clue what's in it either..... You hand over your list, and receive a bundle from the store room, with no labels. Hmmm. I'm going to have to be very careful collating the different parts for the different boards. And I'm going to have to label the components myself, beforehand, to have any chance of getting the right part in the right place.

The best thing about ordering ONLINE is that you don't have to drag yourself around different shops in order to find exactly what you want/need. Or find that they haven't actually got it. Oh, and you get the delight of (often) finding exactly what you want. Oh, and then you recognise just how far online purchasing has come in the last couple of years. Then you get the joy of the anticipation. Then more joy with the delivery. Then you get to unwrap your "pressie/s"!

And wonder, what on earth is it?

At least online stuff that is delivered comes with a despatch note, identifying what is in your parcel.

I'm very impressed with the Farnell and RapidOnline ordering systems. You can copy and paste a list of your parts with optional extra text in the case of Farnell, so I have been able to add my own identifier, as per my components spreadsheet.
My Farnell delivery arrived yesterday afternoon by UPS in a shoebox-sized carton. Everything is in its own bag, labelled with the part number and a brief shop description. That identifier text I submitted has been added onto Farnell's despatch note, so that I can trace the parts by my own identifier, not just the supplier's. Nice. And my RapidOnline order came by Royal Mail this morning.

I'm not impressed by RS, though. I ordered my 3 different items online, and booked them for collection at the local RS trade counter (TC). I thought that was a fine plan. Turns out that RS TC stands for
Really Slow Tree Chopping. I guess.
Anyway, along I went, finding it is at the back of beyond off the bus route, and then a bit further, and then round the corner to the far door, and then a wait. One item appeared. The Chap asked another member of staff. Another wait. A second item appeared from storage elsewhere. Another wait. A third person was roped in at this stage. Another wait. It turned out that my third item, the solder paste, was out of stock. (There seems to be a UK-wide dearth of lead-free solder paste!)
When I'd ordered online, it was all marked "available". Hmmmmph. The Chap then said he'd get my paperwork ready - this was when I think they went out back to chop down the trees! I ended up,
EVENTUALLY, with several sheets of paper and an extra one saying that I HAD paid in full. This all took well over half an hour. So I have to go back with that note in 2 weeks' time, 6th August, when they should have the last item in.
Oh the joy of online ordering!!

Wednesday, 22 July 2009

Every little bit

I have completed my spreadsheet showing all the parts I need for those printed circuit boards I could not purchase as kits. I have found UK alternatives/alternative suppliers for all parts now, and as cheaply as possible (I believe). The components are for the following Generation 3 boards:
  • opto endstop v2.1 - need 3
  • GM3 noise suppressor v1.0 for extruder motor - need 1
  • temperature sensor v2.0 for thermistor - need 1
  • stepper motor driver v2.3 - need 3
plus solder paste and tweezers.

I have linked to the spreadsheet below. There are four sheets; the first contains all the parts required, the other three contain shopping lists for the relevant suppliers, including final costs.

Electronic components for Generation 3 RepRap PCBs

Thanks to Nophead

Yes, that's our very own Manchester-based RepRap Guru, Nophead. (And his wife).
I, rather cheekily, asked if I could go to see Chris' set-up, and HydraRaptor. If you've not read (bits of - it's huge) his blog, do so now. You'll learn heaps. Anyway, I digress. He offered to show me reflow soldering, as he was about to try it for the first time.

Chris came to pick me up (never let strange people you've ONLY met on the internet have your address without having theirs....well, only if you've got a big weapon to hand - it's OK, I took my crutches!) and I spent a few hours talking with him and his wife, watching and learning, and being supplied with drinks and giant cookies.

Chris was trying out a brand new mini-oven and we had our first experience of reflow soldering.
Reading theory and seeing practice are so different. I saw how difficult it was to get the solder precisely positioned, and got to see how much solder was too much. (I learnt which way was up on various components.) We watched the "cooking" in the oven whilst checking the board's temperature over time. I learnt what the increase in temperature rate should be, approximately, and that there is a maximum of 60s at the top (soldering) temperature, to avoid damaging components. I got a feel for how all this should be. Chris showed me which of the finished joints were bowed the wrong way, which were perfect, which good enough. I know how to poke/scrape the solder balls away - more to the point I know how they look.

Next Chris fired HydraRaptor up - the videos with sound don't do it justice! It's quite loud. He selected a small part and printed it. Again, seeing for myself showed me things I didn't appreciate from the videos, such as the hanging baskets for holding the reels of plastic need to be able to twizzle to prevent the plastic, itself, from twisting as it goes into the extruder. I've seen parts being printed in the vid.s, but I'd never seen one being separated from its raft, before. I asked questions about the choice of raft settings, number of layers, fineness etc. Chris allowed me to keep the part printed, so I have a reminder of how the raft was done.

All in all, I had a fun time, I learnt absolutely heaps, got a feel for what's what, and didn't talk about anything else for the next several hours, including in the pub in the evening! So a big thank you to Chris and his wife for an extraordinary day. Cheers!

Thursday, 2 July 2009

Behind the scenes

Surprise! Re-organising my Royal Mail delivery for the Saturday did work! My order from Makerbot arrived in a box labelled "merchandise", signed (or rather printed as before) Zach. This one is lined with bubble wrap. US postage was paid on 19th May, HMRC added their customs charge label dated 01 June. For those interested, customs charges are due for import into the EU when the value is over £18 for a purchase. The VAT I paid on this parcel was £8.66.
I am amazed by the tiny size of the boards - assembling these is going to be a truly fiddly job.

I have spent a couple of weeks looking at parts, and trying to minimize postage and packing costs to get the electronic components sourced in the UK. Some parts I just could not find, so I had to check what type of size etc they were to find equivalents. Once again, I have been very grateful for all the input from the reprap forum, where several people advised me on UK electronics suppliers and how to select substitutes, and even came up with substitutes for me where I'd drawn a blank.

I've learnt that
  • P&P can make a significant contribution to costs if you're only purchasing a couple of parts
  • you can search for manufacturer's component numbers on many sites
  • some technical customer service help is efficient (see below) - yes, really
  • on-site searches aren't much cop - sometimes you can get to other options using Google and the supplier's name
  • the same goes for the forum
  • sometimes it is cheaper overall to buy 25 of an expensive component, with specifications greater than the original specified part, than 100 of the cheaper part
  • even online retailers have a few sites where you can pick up parts yourself = no P&P
  • this is getting even more expensive than I imagined!
I was still looking for solder paste. I have decided to have lead-free (well, I am an environmental scientist, after all). The favoured one, and the one to which I was pointed weeks ago, is still out of stock. There were few options at Farnell, but one didn't have its soldering temperature, not even on the technical details pdf. I went to the manufacturer's website, but still nothing. So I emailed Farnell. Firstly, they acknwledged my email, then emailed to say they didn't know and that they would contact the company. Then they emailed me back with a response the same day! That's what I call good customer service. (Oh, Virgin, Virgin, you've a thing or two to learn!)
I am putting together a spreadsheet of original specifications, replacement part sourced in the UK and its specifications and supplier, and current prices. I need to cycle out to Maplin and RS to pick up a few items, but otherwise all parts are from Farnell or RapidOnline.

I have also taken the top of the B&Q workbench apart, because it really wasn't working - love the height, but... Discovered that the two horizontal arms supporting the wooden tops were not parallel - at all - so the winding/latching mechanisms were strained at silly angles and could not work smoothly. The two aforementioned arms are held by two uprights, which I shall call stilts. The only part orienting the stilts was a bar between them. Unfortunately for me, the bar caused the stilts to be angled in slightly, thereby pushing the upper arms together at one end and apart at the other. The bar turned out to be too short by about a cm. I have removed this bar, and re-assembled without it. Only one clip is being a nuisance now, but that might be because its slide has lost its coating with how it was wedging before.

The other thing I've been investigating (see? Lots going on in the background) is making files for 3D objects. Again, someone on the forum pointed me to software (FREE! or expensive, depending on the version) called David, for turning your 3D objects into scans to build up a 3D image file. Hmmm, interesting. There are a couple of good examples, even with the free version. I have been reading around their forum, too. Seems like another encouraging, friendly, forum with lots of good advice. What, three good fora? Wow!