Tweet
Hi all,
Welcome to part 2 of what is a very long project update ...........................
Continuing on from the modifications in order to improve not only my vacuum forming plugs ( which will result in better parts being produced ), but also my workflow, is taking a considerable amount of time but that can't be helped I'm afraid guys.
As you may of seen from some of my previous vacuum forming results, some things weren't quite working out for me.
The nature of this material ( 3mm ABS ) is amazingly strong, and when heated and cooled it becomes almost as strong as steel .......... I kid you not ! You could say that my plug ( or mould ) as a very bad design, but that's the shape that I need. If the parts required were designed as a one piece unit mounting directly to the van, then I think I would go a different way, but these parts are designed to fit in an already existing part ................. being the original VW headlight mounts. So I have no option than to make these fit that mount. Which means having a flat base with no draft angle on it at all, that's a big no no when it comes to vacuum forming parts, usually these sorts of parts have to be injection moulded ............... a very very expensive procedure, not to mention the machine you need to manufacture them. The flat wall on the 'footing' is causing me a major problem. I just have to find an alternative way of making my parts.
My first tests had me trying this out ................. it was working as I was getting very good definition on my parts but I just couldn't release the part from my plug. So I thought why not spread the base out a bit ( like a wedge ), and add some vent holes in the top of the plug ? this I thought would help to release the part after it's been vacuum formed >>
This part took me almost 2 hours to remove from my plug, as you can see in the picture it's coming out a bit at a time, it's very frustrating not to be able to wedge a screw driver in the gap ( first of all, there is no gap ! ) but if there were, you would be temped to prise it out with something ! But then you would end up breaking your mould
at it times like this that you begin to realise how tough this material is >>
Here's what I came up with ................. and the other reason why I had to make a router table. First thing you have to do is to make a base ( 10mm MDF ) that should be enough to raise the plug, not too much as the higher you raise your plug the more stretching you will get on your finished part. Which results in thin plastic at the top of your part and therefore you lose all the structural integrity of your part. So there's another compromise >>
It stands to reason that if you need a 45° angle ( wedge ) on your base, and that you are using 10mm MDF that your base has to be 10mm bigger than the foot of you plug I: I did mine a little larger just in case ! >>
Then I had to make a router 'template' as I didn't want the router bit anywhere near my resin plug ! I swear I was having a blonde day that day, I just couldn't work it out ! The first 'template' I made was bigger than my base !!! :* Then it dawned on me that I have to work upside down ....... router template ontop and base ( work piece ) underneath ! I:
I was making life very difficult for myself, as previously I had drilled the holes in my plugs to allow for the brass inserts ........ now I had to find and align all 10 of those holes ! And MDF isn't transparent ! >>
In this shot you can just see the 45° router bit mounted in the router table, worked out OK in the end >>
Yeah, loads of faffing about, but it's all for a good cause
>>
When you screw everything together, as I'm using counter sunk M5 machine screws, you simply insert some washes inbetween the 'new' 45° base and the plug, which creates the vacuum holes ( or gap if you prefer ) >>
Now for the vent holes in the top of the vacuum forming plug. I'd previously marked out where I thought the vent holes would be. But I thought I had better double check. As I'm adding vent holes to aid the vacuum forming process, I may as well use the points where the headlight units will be mounted on the final part ........ seems logical ! As a small hole will leave a slight mark in the plastic >>
For this to go right I had to use the only prototype that I know works correctly. A few months ago I had these installed on my van, all four headlight units lined-up correctly, so those are the measurements I have to use. But, ( there's always a 'but' isn't there ) now that my modified resin tooling plug is 2mm bigger all the way round, my previous prototype headlight bracket doesn't fit over the top of my plug ! >>
There was only one thing for it ......................... I had to cut down my existing prototype brackets with my 'trimming jig' and yet to be approved circular slitting saw I set about cutting some plastic. Actually, not a bad exercise this as I can test how effective a normal wood saw cuts plastic ( see Gaz ! ) as opposed to a router bit or milling bit. There's also another benefit to this, as I end up with a top section ( that I need right now ) but the correct profile for cuts in the base that I'll need later >>
At this point it's interesting to point out the thickness of the surrounding base of the formed ABS plastic. As you vacuum form plastics the thickest section of the plastic will be ontop, on a male mould ............... and gradually it will thin toward the bottom as it's getting stretched. Notice how thick that is, and that's a section of the base ! virtually no thickness lost from the initial 3mm ABS I began with, that's an excellent result T: >>
Just as well I didn't drill those holes ! I was 7mm out !
Time for a little precision work ...................... >>
Get this wrong and you'll end up with headlight units that don't sit level, best way I have found for finding the centre of a circle is a draftman' 'thingymijig' ! ......... can't remember the correct term for it right now, but this one' got cross hairs on it as well. And with a 0.5mm drill bit you can be as accurate as possible >>
My other present to one' self is this very handy desk lamp with a x5 magnifying glass on it ................ great for those precise moments
Kind of reminds me of my days I spent as a watch maker >>
And here's the result of all that preparation and hard work .................. one perfectly vacuum formed ABS headlight part T:
And I was able to release the part simply by lowering the platten >>
Now for a little bit of quality control ..................... there really isn't anything to complain about, I mean, the definition is superb, the edges are nice and crisp without being too sharp ( as a sharp edge usually results in a weak section ) all in all I'm quite pleased with that H: time for a pat on the back I think ! >>
And a few more shots for your enjoyment ................... or should I say mine ! I: >>
See how that 'splayed-out' plastic footing has worked, and the indent for the fourth mounting bolt >>
So that's basically how I will be making these headlight brackets, the entire process in a nut shell. Next up, preparing the vacuum formed part for profiling and fitting into the rest of the assembly.
Hope you enjoyed the update and that I didn't bore you all too much ( or put some of you to sleep ) ................. but there's loads more yet ! LOL:
TURK
Welcome to part 2 of what is a very long project update ...........................
Continuing on from the modifications in order to improve not only my vacuum forming plugs ( which will result in better parts being produced ), but also my workflow, is taking a considerable amount of time but that can't be helped I'm afraid guys.
As you may of seen from some of my previous vacuum forming results, some things weren't quite working out for me.
The nature of this material ( 3mm ABS ) is amazingly strong, and when heated and cooled it becomes almost as strong as steel .......... I kid you not ! You could say that my plug ( or mould ) as a very bad design, but that's the shape that I need. If the parts required were designed as a one piece unit mounting directly to the van, then I think I would go a different way, but these parts are designed to fit in an already existing part ................. being the original VW headlight mounts. So I have no option than to make these fit that mount. Which means having a flat base with no draft angle on it at all, that's a big no no when it comes to vacuum forming parts, usually these sorts of parts have to be injection moulded ............... a very very expensive procedure, not to mention the machine you need to manufacture them. The flat wall on the 'footing' is causing me a major problem. I just have to find an alternative way of making my parts.
My first tests had me trying this out ................. it was working as I was getting very good definition on my parts but I just couldn't release the part from my plug. So I thought why not spread the base out a bit ( like a wedge ), and add some vent holes in the top of the plug ? this I thought would help to release the part after it's been vacuum formed >>
This part took me almost 2 hours to remove from my plug, as you can see in the picture it's coming out a bit at a time, it's very frustrating not to be able to wedge a screw driver in the gap ( first of all, there is no gap ! ) but if there were, you would be temped to prise it out with something ! But then you would end up breaking your mould
at it times like this that you begin to realise how tough this material is >>Here's what I came up with ................. and the other reason why I had to make a router table. First thing you have to do is to make a base ( 10mm MDF ) that should be enough to raise the plug, not too much as the higher you raise your plug the more stretching you will get on your finished part. Which results in thin plastic at the top of your part and therefore you lose all the structural integrity of your part. So there's another compromise >>
It stands to reason that if you need a 45° angle ( wedge ) on your base, and that you are using 10mm MDF that your base has to be 10mm bigger than the foot of you plug I: I did mine a little larger just in case ! >>
Then I had to make a router 'template' as I didn't want the router bit anywhere near my resin plug ! I swear I was having a blonde day that day, I just couldn't work it out ! The first 'template' I made was bigger than my base !!! :* Then it dawned on me that I have to work upside down ....... router template ontop and base ( work piece ) underneath ! I:
I was making life very difficult for myself, as previously I had drilled the holes in my plugs to allow for the brass inserts ........ now I had to find and align all 10 of those holes ! And MDF isn't transparent !
>>In this shot you can just see the 45° router bit mounted in the router table, worked out OK in the end >>
Yeah, loads of faffing about, but it's all for a good cause
>>When you screw everything together, as I'm using counter sunk M5 machine screws, you simply insert some washes inbetween the 'new' 45° base and the plug, which creates the vacuum holes ( or gap if you prefer ) >>
Now for the vent holes in the top of the vacuum forming plug. I'd previously marked out where I thought the vent holes would be. But I thought I had better double check. As I'm adding vent holes to aid the vacuum forming process, I may as well use the points where the headlight units will be mounted on the final part ........ seems logical ! As a small hole will leave a slight mark in the plastic >>
For this to go right I had to use the only prototype that I know works correctly. A few months ago I had these installed on my van, all four headlight units lined-up correctly, so those are the measurements I have to use. But, ( there's always a 'but' isn't there ) now that my modified resin tooling plug is 2mm bigger all the way round, my previous prototype headlight bracket doesn't fit over the top of my plug ! >>
There was only one thing for it ......................... I had to cut down my existing prototype brackets
with my 'trimming jig' and yet to be approved circular slitting saw I set about cutting some plastic. Actually, not a bad exercise this as I can test how effective a normal wood saw cuts plastic ( see Gaz ! ) as opposed to a router bit or milling bit. There's also another benefit to this, as I end up with a top section ( that I need right now ) but the correct profile for cuts in the base that I'll need later >>At this point it's interesting to point out the thickness of the surrounding base of the formed ABS plastic. As you vacuum form plastics the thickest section of the plastic will be ontop, on a male mould ............... and gradually it will thin toward the bottom as it's getting stretched. Notice how thick that is, and that's a section of the base ! virtually no thickness lost from the initial 3mm ABS I began with, that's an excellent result T: >>
Just as well I didn't drill those holes ! I was 7mm out !
Time for a little precision work ...................... >>
Get this wrong and you'll end up with headlight units that don't sit level, best way I have found for finding the centre of a circle is a draftman' 'thingymijig' ! ......... can't remember the correct term for it right now, but this one' got cross hairs on it as well. And with a 0.5mm drill bit you can be as accurate as possible >>
My other present to one' self is this very handy desk lamp with a x5 magnifying glass on it ................ great for those precise moments
Kind of reminds me of my days I spent as a watch maker >>
And here's the result of all that preparation and hard work .................. one perfectly vacuum formed ABS headlight part T:
And I was able to release the part simply by lowering the platten
>>Now for a little bit of quality control ..................... there really isn't anything to complain about, I mean, the definition is superb, the edges are nice and crisp without being too sharp ( as a sharp edge usually results in a weak section ) all in all I'm quite pleased with that H: time for a pat on the back I think ! >>
And a few more shots for your enjoyment ................... or should I say mine ! I: >>
See how that 'splayed-out' plastic footing has worked, and the indent for the fourth mounting bolt >>
So that's basically how I will be making these headlight brackets, the entire process in a nut shell. Next up, preparing the vacuum formed part for profiling and fitting into the rest of the assembly.
Hope you enjoyed the update and that I didn't bore you all too much ( or put some of you to sleep ) ................. but there's loads more yet ! LOL:
TURK
Cabinet makers use them all the time, how do you think they manage to make all those intricate joins perfectly everytime ? simple jigs my friends >>
Comment