{"id":274,"date":"2014-01-18T15:28:42","date_gmt":"2014-01-18T15:28:42","guid":{"rendered":"http:\/\/www.henrylahr.com\/?p=274"},"modified":"2020-12-28T11:42:54","modified_gmt":"2020-12-28T11:42:54","slug":"adventures-in-etching","status":"publish","type":"post","link":"https:\/\/www.henrylahr.com\/?p=274","title":{"rendered":"Adventures in etching"},"content":{"rendered":"<p>This is my very first attempt at etching my own PCBs. My goal was to design a two-sided board to hold four 256K serial EEPROMs (<a href=\"http:\/\/www.hobbytronics.co.uk\/eeprom-24lc256?keyword=eeprom\">24LC256 Serial I2C EEPROM<\/a>). The PCB is about 5cm long as you can see from the 0.1&#8243; pitch. The lesson I learned was about using the correct paper to transfer the laser printer toner. I tried HP glossy photo paper first and failed spectacularly. This is not to say that the toner could not be transferred with this paper &#8211; the resolution is great. The only problem is that the glossy finish sticks to the board and cannot be removed without destroying the toner layer. I then switched to ordinary matte paper, which worked surprisingly well.<\/p>\n<p>The image below shows the PCB after toner transfer, ironing each side for about two minutes and soaking in water for a few minutes. Removing the paper by rubbing slightly with your finders is a breeze. You can see that the toner was not properly transferred in a few places. My suspicion is that this is either due to poor cleaning as suggested on some websites or the paper soaking up the toner. I am curious as to whether anyone else had similar difficulties.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-275\" alt=\"eeprom_board_1\" src=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_1.jpg\" width=\"671\" height=\"189\" srcset=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_1.jpg 671w, https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_1-300x84.jpg 300w\" sizes=\"auto, (max-width: 671px) 100vw, 671px\" \/><\/p>\n<p>Using Eagle&#8217;s default 12(?)mil padding when pouring the copper turned out to be quite tricky. I had to cut many shorts that remained after my impatient etching. I will probably use at leat 20mil next time. A trace width of 32mil works perfectly given the paper quality. I could even afford to be a little sloppy when rubbing off the paper as you can see in the lower trace and some pads in the picture. This is the board after cleaning with acetone:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-276\" alt=\"eeprom_board_2\" src=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_2.jpg\" width=\"671\" height=\"178\" srcset=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_2.jpg 671w, https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_2-300x79.jpg 300w\" sizes=\"auto, (max-width: 671px) 100vw, 671px\" \/><\/p>\n<p>The finished board with EEPROMs (in turned pin sockets), a 100nF decoupling capacitor and a header to connect to my Arduinos:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-277\" alt=\"eeprom_board_3\" src=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_3.jpg\" width=\"671\" height=\"167\" srcset=\"https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_3.jpg 671w, https:\/\/www.henrylahr.com\/wp-content\/uploads\/2014\/01\/eeprom_board_3-300x74.jpg 300w\" sizes=\"auto, (max-width: 671px) 100vw, 671px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>This is my very first attempt at etching my own PCBs. My goal was to design a two-sided board to hold four 256K serial EEPROMs (24LC256 Serial I2C EEPROM). The PCB is about 5cm long as you can see from the 0.1&#8243; pitch. The lesson I learned was about using the correct paper to transfer &hellip; <\/p>\n<p><a class=\"more-link btn\" href=\"https:\/\/www.henrylahr.com\/?p=274\">Continue reading<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-274","post","type-post","status-publish","format-standard","hentry","category-musings","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/posts\/274","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=274"}],"version-history":[{"count":4,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/posts\/274\/revisions"}],"predecessor-version":[{"id":667,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=\/wp\/v2\/posts\/274\/revisions\/667"}],"wp:attachment":[{"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=274"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=274"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.henrylahr.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=274"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}