TobyBorlandOriginal

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Assembly of a Toby Borland Original PlyRap

Introduction

These are the build instructions for a plywood Version 1.0 Darwin RepRap. This is a duplicate of the one exhibited at the Science Museum (London, England) in conjunction with SMARTlab. Toby was originally working to fairly tight deadlines and the documentation lagged the actual build. This document is aimed at contributing to that documentation and complements the CAD files which can be found at Sourceforge in the CVS repository. As this documentation is written after the fact and I am in many ways catching up to the detailed work that went before, any errors and mistakes are likely to be mine. Feedback and observations are welcome.

Construction Hints and Tips

Working with Plywood

Plywood whilst being an engineered material shares a whole bundle of features with the wood it was made from. Key features to note, then work with and around are :-

  • Dimensional stability Wood in general is a fairly dynamic thing in that it changes under the influence of the environment it finds itself in. Most notable is that it absorbs water and will shrink when dried and expand when wet. Even boards marked as for exterior use do the same. The main difference between interior and exterior boards is the glue used. The actual ply's are the same wood and react the same to the presence of water. Keep you parts somewhere dry until assembly is complete and when finished paint or varnish them to seal the surfaces.
  • Dimensional Precision Plywood is manufactured to within a nominal dimensional specification plus or minus a specified amount of error. This is of course then also affected by the observations above. Expect that the parts whilst being designed to the correct sizes and tolerance will be different when cut out of actual material because of this. Be prepared to file, sand and cut your way to success.
  • Gluing Use a water based wood glue, avoid impact adhesives as you don't get enough time with them to manipulate the alignment of components before they are grabbed permanently by the adhesive. You can use standard PVA glue quite successfully and it is sometimes possible to separate incorrectly PVA glued items by soaking in water. Be very mindful of the above notes re dimensional stability though. Soaking should really be a last desperate resort.
  • Filling Holes and voids can be filled with any number of over the counter fillers from DIY stores. A favorite carpenters trick is to mix fine saw dust with wood glue and use this as it is both cheap and matches the colour of the wood being used.
  • Wood Grain Whilst Plywood has its plys layered with the grain running at 90 degrees per layer for strength be aware that when cutting, sharp tools will attempt to follow the grain of the layer you are cutting through. Despite your best attempts otherwise, take great care with your fingers, you will need them for the rest of the assembly work. Similarly when filing, sanding and sawing the surface ply's will rip along the grain and look a bit of a dog. This can be avoided with care. Scoring the surface ply with a sharp blade can reduce the surface ripping along the grain.

The components in this design are made mostly from the same thickness of plywood. This means that where a component needs to be of a greater thickness several pieces of the plywood are glued together to achieve this. This technique is known as lamination and can create parts with great strength if a few simple rules also common to gluing wood are followed.

  1. Trial Assembly Assume that none of your pieces will fit instantly and perfectly together. Assemble each component dry, that is without any glue. Sand. file and cut your way until all the pieces for that particular component fit correctly together. Only when you are happy contemplate gluing them together.
  2. Applying Glue Don't go wild with the glue any excess just squeezes out when you clamp your work up and needs cleaning off. Apply a thin regular film to each surface to be glued. Leave no voids or dry patches. Think of it as spreading butter frugally across a piece of cold toast. When clamped up wipe off any excess with a damp rag. Any you can;t get to can be cut away with a sharp knife after it has dried.
  3. Clamping Glued wooden pieces and especially laminations are at their strongest when they have been clamped together for the duration of the time it takes the glue to set. Check you glue bottle for the instructions as to how long this is. You can use anything that will clamp up including a vice, nuts and bolts or dedicated clamps. If you are short of clamps and need to get on with the job clamp the pieces for at least the first hour or so.
  4. Work in Stages Freshly glued laminations and pieces tend to slip until the glue has sufficiently dried, this is great for adjusting alignment. It is a pain though when you want to clamp up the work. Avoid clamping at angles to the glued joint, always clamp across the join at about 90 degrees. Do your gluing in stages and allow one stage to dry before progressing onto the next. arrange your stages so that it is only necessary to clamp in the one orientation per stage. You can glue as many laminations as you have clamps big enough for in a given stage providing you can keep the pieces aligned. Use pins, nuts and bolts as clamps and to keep pieces aligned as the glue dries.

The picture below shows a stage that has been glued with my usual wood working glue and is clamped in a vice with soft jaws taped over the vice jaws so they don't mark the soft surface of the ply wood. I have put a nut and bolt through the laminations to keep them aligned and to keep them clamped when I release the part from the vice after the first hour. While that part continues to dry I can be getting on with the next one. Use washers with the nut and bolt to spread the clamping force and avoid marking the surface of the pieces.

  • Clamped Stage:
TobyBorlandOriginal-Clamping.JPG

It is worthy of note that laminating thin plywood to make thicker pieces if glued correctly will create components with greater strength than working with thicker plywood. This is due to the way plywood is constructed. The outer layers are made from "Best" wood that has a better look and greater strength than the core wood which is a lower grade filler. thicker plywood has more filler. Where as thin plywood laminations contain more "Best" wood and consequently have a greater assembled strength.

A word to the wise, I originally intended to set off and hand cut a set of components to do this build. Toby managed to talk me out of it. Having studied the components and completed the first set of Bed Corner Brackets I now fully realize Toby's advice was sound. His design was specifically made up for laser cutting and many of the components are cut with a precision that is not possible with other tooling. The Kerf (the bit that is lost during cutting due to tool width, usually as sawdust) is so very fine with a Laser cut. Add to this the facts that the Laser burn heat seals the edges and the lack of mechanical distress to the cut edges and you can see how work this fine with a material like plywood is only really possible using laser cut pieces.

Separating the Pieces

The pieces arrive still in their sheet form and need to be separated out. As noted above plywood needs a bit of the delicate touch on pieces that are this fine. Particularly if you have kept your costs down by only ordering just enough of the parts that you need. Here's some tips to help make it work out.

Put a couple of hours aside to seperate out all of the pieces. Do them all in one go. It can be tedious work but once you have got into a pattern of working it will soon be done.

The laser often has not cut completely through the ply wood. This is for a variety of reasons. In most cases this is only the last ply that is just hanging on.

Press such parts out gently by hand from the Back

  • Back:
TobyBorlandOriginal-Back.JPG

To the front

  • Front:
TobyBorlandOriginal-Front.JPG


Press on the waste piece, if any ripping along the grain happens then it will be the waste pieces that are messy and you can ignore them.

To avoid the ripping score along the kerf lines before pressing.

  • Score First:
TobyBorlandOriginal-ScoreFirst.JPG


Keep all the bits until you have completely finished making the components up. I am still finding bits that I should have kept amongst the waste and conversely waste in amongst the good bits. If when you have assembled all your components you have something left and it can not possibly be part of a finished component than it must be waste and can be thrown away. Some of those long thin stick like waste bits are also great for use as disposable glue spreaders.

  • Finished Waste:
TobyBorlandOriginal-FinishedWaste.JPG

Note the tools shown in the picture below. These were all the tools that I needed to separate the pieces and do any initial obvious tidying up. The needle file was used to tidy up the teeth on the drive belt pulleys as these are very fine.

  • Finished Good:
TobyBorlandOriginal-FinishedGood.JPG

Assembling the Jigsaw Pieces into Components

Before

The jigsaw laid out. Before starting check that you have all the pieces by laying them out somewhere where they won't get disturbed. This will also help you easily locate the parts you need for each component as you come to assemble it.

  • The pieces laid out:
TobyBorlandOriginal-Layout.JPG

Resealable plastic bags are great for keeping the more numerous components together and organizing things.

Bed Corners

Dig out all the pieces that you have laid out and that look like these. You are assembling 4 of these so there should be 4 sets of pieces as per the BC1 photo. Proceed to dry fit them together as per photographs BC1 through BC7.

  • BC1:
TobyBorlandOriginal-BC 1.jpg
  • BC2:
TobyBorlandOriginal-BC 2.jpg
  • BC3:
TobyBorlandOriginal-BC 3.jpg
  • BC4:
TobyBorlandOriginal-BC 4.jpg
  • BC5:
TobyBorlandOriginal-BC 5.jpg
  • BC6:
TobyBorlandOriginal-BC 6.jpg
  • BC7:
TobyBorlandOriginal-BC 7.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Four Bed Corners Completed:
TobyBorlandOriginal-BC4Done.JPG

Where did that bottle of beer come from ???

Bed Constraint Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 2 of these so there should be 2 sets of pieces as per the BCS1 photo. Proceed to dry fit them together as per photographs BCS1 through BCS3.

  • BCS1:
TobyBorlandOriginal-BCS 1.jpg
  • BCS2:
TobyBorlandOriginal-BCS 2.jpg

Watch those mounting holes they bolt to the holes on the Bed Clamp component and are offset towards the Bed Clamp. If you get them the wrong way around you will loose a bunch of valuable adjustment when it comes time to assemble the machine.

  • BCS3:
TobyBorlandOriginal-BCS 3.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Two Constraint Brackets Complete:
TobyBorlandOriginal-BCS2Done.JPG


Corner Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 8 of these so there should be 8 sets of pieces as per the CB1 photo. Proceed to dry fit them together as per photographs CB1 through CB10.

  • CB1:
TobyBorlandOriginal-CB 1.jpg
  • CB2:
TobyBorlandOriginal-CB 2.jpg
  • CB3:
TobyBorlandOriginal-CB 3.jpg
  • CB4:
TobyBorlandOriginal-CB 4.jpg
  • CB5:
TobyBorlandOriginal-CB 5.jpg
  • CB6:
TobyBorlandOriginal-CB 6.jpg
  • CB7:
TobyBorlandOriginal-CB 7.jpg
  • CB8:
TobyBorlandOriginal-CB 8.jpg
  • CB9:
TobyBorlandOriginal-CB 9.jpg
  • CB10:
TobyBorlandOriginal-CB 10.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Eight Corner Brackets Complete:
TobyBorlandOriginal-CB8Done.JPG

Diagonal Tie Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 20 of these so there should be 20 sets of pieces as per the DB1 photo. Proceed to dry fit them together as per photographs DB1 through DB3.

  • DB1:
TobyBorlandOriginal-DB 1.jpg
  • DB2:
TobyBorlandOriginal-DB 2.jpg
  • DB3:
TobyBorlandOriginal-DB 3.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Twenty Diagonal Tie Brackets Complete:
TobyBorlandOriginal-DB20Done.JPG

X Idler Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the IB1 photo. Proceed to dry fit them together as per photographs IB1 through IB7. If the will to live was leaving you whilst gluing the last 20 this one should be more fun.

  • IB1:
TobyBorlandOriginal-IB 1.jpg
  • IB2:
TobyBorlandOriginal-IB 2.jpg
  • IB3:
TobyBorlandOriginal-IB 3.jpg
  • IB4:
TobyBorlandOriginal-IB 4.jpg
  • IB5:
TobyBorlandOriginal-IB 5.jpg
  • IB6:
TobyBorlandOriginal-IB 6.jpg
  • IB7:
TobyBorlandOriginal-IB 7.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One X Idler Bracket Complete:
TobyBorlandOriginal-IB1Done.JPG

X Carriage

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the XC1 photo. Proceed to dry fit them together as per photographs XC1 through XC4.

  • XC1:
TobyBorlandOriginal-XC 1.jpg
  • XC2:
TobyBorlandOriginal-XC 2.jpg
  • XC3:
TobyBorlandOriginal-XC 3.jpg
  • XC4:
TobyBorlandOriginal-XC 4.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One X Carriage Complete:
TobyBorlandOriginal-XC1Done.JPG

My "Half-Day" tea mug has snuck in to the frame. It said it was jealous of the beer bottle.

X Constraint Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the XIB1 photo. Proceed to dry fit them together as per photographs XIB1 through XIB3. The Darwin Glossary calls this component an X Constraint Bracket and Toby has these parts and photo's labeled up as XIB. We will stick with the Glossary nomenclature though as it makes it easier to later work out which Plastic Darwin part is intended to replace which Ply Darwin Part.

  • XIB1:
TobyBorlandOriginal-XIB 1.jpg

Be very careful when filing the vertical slot in the two upright laminations. The bearing hole actually runs through to the tag slot. In itself this isn't problematic but the other side of the piece is quite thin. Too much force applied to the piece in the wrong way can snap the ply pieces.

  • XIB2:
TobyBorlandOriginal-XIB 2.jpg
  • XIB3:
TobyBorlandOriginal-XIB 3.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One X Constraint Bracket Complete:
TobyBorlandOriginal-XIB1Done.JPG

X Motor Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the XMB1 photo. Proceed to dry fit them together as per photographs XMB1 through XMB10. This component is one of the more complex ones to assemble. If you have built these components in sequence by the time you get here you should have no problems though.

  • XMB1:
TobyBorlandOriginal-XMB 1.jpg
  • XMB2:
TobyBorlandOriginal-XMB 2.jpg
  • XMB3:
TobyBorlandOriginal-XMB 3.jpg
  • XMB4:
TobyBorlandOriginal-XMB 4.jpg
  • XMB5:
TobyBorlandOriginal-XMB 5.jpg
  • XMB6:
TobyBorlandOriginal-XMB 6.jpg
  • XMB7:
TobyBorlandOriginal-XMB 7.jpg
  • XMB8:
TobyBorlandOriginal-XMB8.JPG

A useful tip. There are so many tags and slots to match up at this stage it is easy to miss filing one up or even some may just not fit without further adjustment. When you dry fit the plate mark the tags and slots that need more work lightly with a pencil cross. When you take it off again then to make the adjustments you won't forget which of the many it was that you needed to work on. If you look closely in the photograph you will be able to see the ones I missed marked with a cross.

  • XMB9:
TobyBorlandOriginal-XMB 9.jpg
  • XMB10:
TobyBorlandOriginal-XMB 10.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One X Motor Bracket Complete:
TobyBorlandOriginal-XMB1Done.JPG

Y Bearing Mount

Dig out all the pieces that you have laid out and that look like these. You are assembling 3 of these so there should be 3 sets of pieces as per the YBM1 photo. Proceed to dry fit them together as per photographs YBM1 through YBM4.

  • YBM1:
TobyBorlandOriginal-YBM 1.jpg
  • YBM2:
TobyBorlandOriginal-YBM 2.jpg
  • YBM3:
TobyBorlandOriginal-YBM 3.jpg
  • YBM4:
TobyBorlandOriginal-YBM 4.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Three Y Bearing Mounts Complete:
TobyBorlandOriginal-YBM3Done.JPG

OK there are four in the photo. I made a spare and wanted to see if you are still awake.

Y Motor Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the YMB1 photo. Proceed to dry fit them together as per photographs YMB1 through YMB5.

  • YMB1:
TobyBorlandOriginal-YMB 1.jpg
  • YMB2:
TobyBorlandOriginal-YMB 2.jpg
  • YMB3:
TobyBorlandOriginal-YMB 3.jpg
  • YMB4:
TobyBorlandOriginal-YMB 4.jpg
  • YMB5:
TobyBorlandOriginal-YMB 5.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One Y Motor Bracket Complete:
TobyBorlandOriginal-YMB1Done.JPG

Z Studding Tie

The Z Studding Tie in the glossary is pretty much nothing more than what it's name suggests. Toby has improved on this slightly to make the Z axis run somewhat smoother etc by reformatting it to include a bearing. Which makes it realy more like a Z Bearing Bracket. As earlier we will stick with the glossary description although its function here is slightly different.

Dig out all the pieces that you have laid out and that look like these. You are assembling 3 of these so there should be 3 sets of pieces as per the ZBBS1 photo. Proceed to dry fit them together as per photographs ZBBS1 through ZBBS3.

  • ZBBS1:
TobyBorlandOriginal-ZBBS 1.jpg
  • ZBBS2:
TobyBorlandOriginal-ZBBS 2.jpg
  • ZBBS3:
TobyBorlandOriginal-ZBBS 3.jpg

Be careful with the alignment. You need to be able to fit the bearing in. Filing the inside of a round hole with a dead end is not fun.

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • Z Studding Ties Complete:
TobyBorlandOriginal-ZBBS3Done.JPG

Z Motor Bracket

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the ZMB1 photo. Proceed to dry fit them together as per photographs ZMB1 through ZMB5.

  • ZMB1:
TobyBorlandOriginal-ZMB 1.jpg
  • ZMB2:
TobyBorlandOriginal-ZMB 2.jpg
  • ZMB3:
TobyBorlandOriginal-ZMB 3.jpg
  • ZMB4:
TobyBorlandOriginal-ZMB 4.jpg
  • ZMB5:
TobyBorlandOriginal-ZMB 5.jpg

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • One Z Motor Bracket Complete:
TobyBorlandOriginal-ZMB1Done.JPG

Z Toothed Pulley

Dig out all the pieces that you have laid out and that look like these. You are assembling 4 of these so there should be 4 set of pieces as per the ZTP1 photo. Proceed to dry fit them together as per photographs ZTP1 through ZTP3.

  • ZTP1:
TobyBorlandOriginal-ZTP1.JPG
  • ZTP2:
TobyBorlandOriginal-ZTP2.JPG
  • ZTP3:
TobyBorlandOriginal-ZTP3.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The dry fitting is not much of a challenge as there is nothing to slot together. However you will have noticed that the two center laminations have all the tiny teeth on them that engage with the 2.5mm drive belt. These must line up as accurately as possible if you want the drive belt teeth to mesh with the pulley teeth.

Attempting to get good alignment of such fine teeth without glue ridges in the middle looks to be near impossible but here is a way. Glue the two inner laminations together first using an M8 and M5 Nut and Bolt to clamp them in alignment. Wood glue is fairly slow to set so you have enough time to slide each lamination around the little that it does move to get the best possible alignment of the two halves of the teeth. Let the glue set enough so that it wont move but so that the glue that was squeezed out has not yet set. Use a steel blade to scrape between each pair of teeth in rotation to clear the glue out of the slot. This sounds fiddly and is a little but is done fairly quickly and gives acceptable results. Example implements to use for the teeth cleaning are the back of an Exacto craft knife blade, a junior hacksaw blade etc.

Finally when the glue has fully set sandwich the results between the top and bottom laminations. Again use bolts to clamp them while the glue sets.

The finished results should look something like this.

  • Four Z Toothed Pulleys complete:
TobyBorlandOriginal-ZTP4Done.JPG

Toby Also supplied some last minute options in the form of a set of inner laminations that are patterned for large pitch ball type plug chain. Assembly for these is as for the finer toothed variants above but clearly the teeth are a lot easier to work with.

  • ZTPC1:
TobyBorlandOriginal-ZTPC1.JPG

The finished results should look something like this.

  • Four Z Toothed Pulleys for Ball Chain complete:
TobyBorlandOriginal-ZTPC4Done.JPG

Z Belt Splicing Jig

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the ZBSJ1 photo. Proceed to dry fit them together as per photographs ZBSJ1 through ZBSJ2.

  • ZBSJ1:
TobyBorlandOriginal-ZBSJ1.JPG
  • ZBSJ2:
TobyBorlandOriginal-ZBSJ2.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • ZBSJ1Done:
TobyBorlandOriginal-ZBSJ1Done.JPG

Use this jig along with a piece of the scrap plywood to help keep the Z toothed belt aligned as you splice it into a continuous loop.

Straight Extruder Motor Support

The Straight Extruder Motor Support was a late addition of Toby's. Toby found that mounting the feed motor further away from the extruder feed assembly allowed a straight rigid drive shaft to be used whilst avoiding fouling the feedstock. Toby also arranged that the Solarbotics GM3 could be optionally replaced with the Tamiya 72001 epicyclic geared motor giving constructors more options for experimentation.

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the ZMB1 photo. Proceed to dry fit them together as per photographs ZMB1 through ZMB5.

  • SEMS1:
TobyBorlandOriginal-SEMS1.JPG
  • SEMS2:
TobyBorlandOriginal-SEMS2.JPG
  • SEMS3:
TobyBorlandOriginal-SEMS3.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like SEMS3 but with glue on.

Extruder Polymer Guide

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the EPG1 photo. Proceed to dry fit them together as per photographs EPG1 through EPG6.

  • EPG1:
TobyBorlandOriginal-EPG1.JPG
  • EPG2:
TobyBorlandOriginal-EPG2.JPG
  • EPG3:
TobyBorlandOriginal-EPG3.JPG
  • EPG4:
TobyBorlandOriginal-EPG4.JPG
  • EPG5:
TobyBorlandOriginal-EPG5.JPG
  • EPG6:
TobyBorlandOriginal-EPG6.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • EPG1Done:
TobyBorlandOriginal-EPG1Done.JPG


Extruder S H

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the ESH1 photo. Proceed to dry fit them together as per photographs ESH1 through ESH4.

  • ESH1:
TobyBorlandOriginal-ESH1.JPG
  • ESH2:
TobyBorlandOriginal-ESH2.JPG
  • ESH3:
TobyBorlandOriginal-ESH3.JPG
  • ESH4:
TobyBorlandOriginal-ESH4.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • ESH1Done:
TobyBorlandOriginal-ESH1Done.JPG

Extruder Clamp

Dig out all the pieces that you have laid out and that look like these. You are assembling 1 of these so there should be 1 set of pieces as per the EC1 photo. Proceed to dry fit them together as per photographs EC1 through EC4.

  • EC1:
TobyBorlandOriginal-EC1.JPG
  • EC2:
TobyBorlandOriginal-EC2.JPG
  • EC3:
TobyBorlandOriginal-EC3.JPG
  • EC4:
TobyBorlandOriginal-EC4.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • EC1Done:
TobyBorlandOriginal-EC1Done.JPG

Opto Sensor Board

Dig out all the pieces that you have laid out and that look like these. You are assembling 6 of these so there should be 6 sets of pieces as per the OSB1 photo. Proceed to dry fit the two pieces of each component together.

  • OSB1:
TobyBorlandOriginal-OSB1.JPG

When you have dry fitted them all having filed and sanded your way to success you are ready to glue them. The finished results should look something like this.

  • OSB6Done:
TobyBorlandOriginal-OSB6Done.JPG

After

Here are the finished components laid out awaiting assembly into a working machine. You will notice in the photograph that I have already started to fit nut's, bolt's and bearings into the components.

  • The components laid out:
TobyBorlandOriginal-after.JPG

Assembling the components into a working machine

Economy

The original Darwin RP'd parts all use Cap Head or Socket Head machine screws. These screws are of a variety of lengths each appropriate for the task. The RP'd plastic parts are often made such that clearances for Pan Head screws are insufficient without modification. As the ply components are based on the original plastic components they were also designed for use with Cap Head machine screws.

In the interests of economy I have used Pan Head machine screws in as few lengths as possible. This has made it possible to get best price (pence per screw, nut & washer) by buying bigger packs. Pan Head machine screws cost less than their Cap or Socket headed equivalents. Do shop around it is quite surprising what the price breaks work out at and will be different in your locality. I found M5 30mm machine screws to be half the cost of M5 20mm screws from my local supplier when bought in packs of 250 or more.

Where the screw was unsightly or ridiculously long I have used a Dremel cut off tool to trim them down to a more manageable size. If you don't have a Dremel or equivalent a junior hacksaw and file can be used instead.

I also used the Dremel tool with a suitable sized cutter/burr and sanding drum to make additional clearance for the Pan head on the screws where this was necessary or trim up the Pan Head. Again if you don't have a Dremel or equivalent the files and craft knives used to make up the components can be used.

The original Darwin and BOM presumes that maximum use will be made of smooth M8 Rod. In practice you may well find that M8 Studding ie threaded M8 Rod actually costs less. Any rod in the design which doesn't support a sliding bearing is fair game to exchange for studding with the attendant cost savings.

The rotary bearings Toby designed for are 608ZZ bearings (Deep Grooved, Ball Bearing, 8mm Bore with 2 Seals) and are available at their most cost effective as skateboard bearings either from eBay or your local skateboard shop. Greater ABEC numbers are allocated to bearings with tighter tolerances. ABEC5 should be plenty good enough although if you can get anything greater for the same price or less these are worth having.

Convenient sources for most of the components you might need if you can not get them locally can be found [PartsSupplies here] this includes the RRRF online store.

Preperation for assembly

Assembling your machine

As the completed components are largely interchangeable with RP'd Darwin plastic components all the existing assembly instructions and BOM details can be followed. Of course in this case we are using the Ply Components instead of plastic ones. Check out he "Gotchas" section for notes on the things that are close but close enough and might catch you out.

[AssemblingDarwinMachinery Cartesian assembly instructions (Mechanical) can be found here] courtesy of VikOlliver and EdSells

[AssemblingDarwinElectronics Cartesian assembly instructions (Electrical) can be found here] courtesy of ZachSmith and EdSells

[RepRapOneDarwinThermoplastExtruder Extruder assembly instructions can be found here] courtesy of AdrianBowyer.

[Generation2Electronics Electronic assembly instructions can be found here] courtesy of AdrianBowyer and I believe ZachSmith.

Gotchas

Check here whilst you are assembling your machine, for things that look like they should be the OK or the same but are not quite. These will probably catch you out as they did me.

  1. You will need to counter sink the Z Motor Bracket top mounting bolt head so that your stepper motor can fit flush into place.
  2. The stub rods used with the Y Idler that the BOM describes as being 70mm need to be a touch longer for use with the Ply parts. 100mm should be sufficient. Do trial fit them using some spare rod to get a correct measurement any surplus can poke out of the top. When you progress to a Darwin built from printed components these can be shortened if necessary.
  3. The corner blocks that support the Y Idler Bracket can get very congested with the grub screws to fix everything in place even to the point of one fouling the placing of another. Easiest way around this is to make the short stub rods from threaded stud rather than bar and fix them in place using M8 nuts top and bottom of the corner block.
  4. The BOM for the non RP parts for the Extruder calls for 2 brass bearings of 11mm long to be cut from M6 brass rod. In actuality the Ply Rap extruder bearing holes are 6mm long by 10mm wide. So cut your bearing pieces from M10 rod and make them 6mm long.

The finished machine

Printing out the Shot Glass

Acknowledgments

-- Main.AndyKirby - 10 Jul 2008