I’ve searched a bunch and couldn’t find anything. How do people make their flat patterns to cut out carbon/glass?
Outside of trial and error, there are some software programs (generally tied to CAD systems) that work. One that I just saw this morning is called TerraFlat and works with Rhino software. FiberSIM, I believe, also can take curved, non-developable surfaces and flatten them out.
One good way is to lay tape down on to your mould (usually down the center), draw a straight reference line with marks ever x distance apart (depending on geometry change). Measure perpendicular to this with a flexible tape measure following the surface shape. Input these points measured in to a 2D drawing program. This works very well for some, can be time consuming for others.
Great idea! That might be a great way to avoid some of the trial and error.
I would always do the trial and error method, but I would use a piece of air weave. Just cut the piece out, trim it, and tape pieces on if need be. Add a little bit of area around the air weave and this will usually get me close enough without much waste.
It depends on the size of the mold. On small ones I just cover the entire mold surface with strips of masking tape. I then trace the cuts/edges, pull the masking tape off in one big sheet and stick it to the template material. You can also just stick the mold in a vacuum bag, pull vacuum, trace right onto the vacuum bag, then stick the vacuum bag onto your template material and cut on the lines.
A Joggle Stick can be a useful tool for making patterns.
Easy
just layup a light fglass skin in your mould and release it out.
Then cut where appropriate to try and flatten it out onto your bench or floor.
Then just trace around it onto a flat pattern material like plywood or a stable plastic film and there’s your pattern.
From that you can fine tune it further with trial and error if needed.
Im interested in this subject too. Especially in knowing the limits of how much a cloth can drape (mainly 2x2 3k twill). I’m trying to do a Lotus 7 nose cone with the least amounts of seams possible.
simulayt which is either a plugin to catia or previously solidworks
more useful is exactflat which was developed for developing fabric patterns
What do you guys use for digitizing hand cut patterns? Other than measure and CAD. I’ve used a digitizer that was a large format tablet-esq setup before, don’t recall the exact make of it. Just wondering what other methods people have used to get a 1:1 hand cut pattern in to CAD, for use with a automated cutter.
Most of my ply patterns are generated using Catia, but I don’t believe it should fully replace the ability to make a quick off the shop floor pattern.
if you have an automated cutter such as Gerber DCS2500 you can use the pen or laser to digitize.
I have a really good method for this. Take some thin, inexpensive fiberglass and wet it out with PVA in the mold. Let it cure hard and then take a sharpie marker and trace the outside of the mold or where you desire the fabric to end.
Pop the cured fiberglass out of the mold and place it on a piece of rigid sheet plastic (I like .06 thick) from the hardware store. Dissolve the PVA by brushing water onto the part. Continue to brush it with water until the fabric is completely flat on the plastic. Let it dry and then trim the plastic to the sharpie line. Then you have a perfect pattern to cut your dry fabric too.
I usually like to cut my fabric say .5-1" outside the pattern to make sure that I have enough for room for positioning the fabric in the mold.
Andy,
I like the vacuum bag idea, sounds easiest to me, I’ll try that.
I have a bunch of patterns to make in the next few weeks… after I get the pattern from the mold I have to digitize. I have one of the those table type digitizers that directly inputs points and creates a DXF. Seems to work fairly well but, I’m sure it’ll be a bit more tricky on the large and long parts. I then cut using a cnc cutting table.
I wish the engineers would just make the patterns right from cad but, they’re resistant to doing it for some reason…