Loomio
Wed 14 Mar 2018

Fiberglass Reinforced Composite Hand

DC
David Chen Public Seen by 376

My partners and I own a Onyx Pro from Markforged, and it does fiberglass reinforced parts that are incredibly strong. The carbon nylon base material also has very good material properties. I've always wondered what a full hand built with this printer with parts reinforced with fiberglass where ever possible would be like.

I know this company's printers have been used to design prosthetics before, but I don't know of any hands. I've attached the material data sheet on the carbon nylon and fiberglass at the end. The carbon nylon has an extremely high heat deflection (145C) and is very durable to abrasion and sheering. I printed a wheel hub for a friend who works in a skateboard wheel company to do destructive testing, and they were unable to break it entirely because it just bent with the force. Sounds like a great material for prosthetics since it cant snap and produce sharp jagged edges.

The material is much more expensive than off the shelf ABS at about $200/kg, and the fiberglass is also quite expensive though you don't really use a lot of it. I'd be very surprised if the material costs went $100, but I'd budget $150 for the 3D print material just in case.

I'm also interested in whether or not an easier-to-assemble hand can be made using this company's technology that doesn't require fasteners which can get lost.

http://www.rpsupport.co.uk/downloads/rps_markforged_data_sheets/markforged_materials_datasheet.pdf

EDIT: Oh wow, I didn't realize this thing ran long ago and just got bumped on the facebook page. Woops.

DC

David Chen Wed 14 Mar 2018

So I downloaded an iron man hand from thingiverse and sliced the largest part. Maybe I'm wrong and it will cost more than $100. Its a bit hard to tell what parts are ornamental with this hand design and what parts need reinforced.
https://imgur.com/a/XKypl

https://www.thingiverse.com/thing:1347022/#files

RB

Rich B Wed 14 Mar 2018

Sounds interesting. Are you requesting funds and a vote?

JS

Jon Schull Wed 14 Mar 2018

Sounds great!

Lower limb Prosthetics are our frontier and need strength.

Rich's comment is appropriate: if not seeking a vote, you'll get more collaboration in the G+ and Facebook communities.

DD

Doc Davies Thu 15 Mar 2018

We also have access to a Markforged Printer (Mark Two) printer. We are testing carbon fiber reinforced 3D printed objects for both robotics and prosthetic applications. We find the CF reinforced parts "virtually" indestructible. We've printed one of the leg prosthetics whose files are currently on the web and are doing wear and destructive testing. They hold great promise. The only issue we see is mild deformation, and we're testing to see if mitigated by design and allow the full use of parts. The only issue, the printer itself is almost ~$15K, and the materials for printing are rather expensive.

DC

David Chen Fri 16 Mar 2018

@richb I mostly want to put the printer to use when its not doing anything else. I have a 'Toy-Story'-esque philosophy when it comes to tools, where I'm not happy with shiny tools that just sit around. But due to the high cost of proprietary materials, I'd like to be reimbursed as I'm still paying off the printer. So if theres a good application (I never even considered lower prosthetics until now), I'd like to apply to do the printing.

@jonschull Wiretapping?

@docdavies If deformation is an issue, I can try printing it with the carbon nylon (onyx). Its much stiffer than the original base nylon, which was quite rubbery. 95% of our prints dont even use reinforcement thanks to it. The material cost is much more than an ABS hand, but I think if parts are selectively reinforced, a handful of key components may give most of the benefits. But even if it used an entire KG of material, $200 + fiber is still a bargain compared to buying a FDA prosthetic of any kind. Printer accessibility is definitely an issue, but we might be able to reach out to MF to see if they want to set up some kind of partnership where people can earn points towards new cartridges by printing during downtime. It would be great exposure for them as a company, as most people I know have never heard about them.

DD

Doc Davies Fri 16 Mar 2018

We do use the Onyx. It is harder...but under great stress, it still deforms. We are talking robotic arm applications extending 15-20 lbs on a 6 ft lever arm essentially. Now with the prosthetics, it's not that big an issue, but we still need to study it. Particularly with the consideration of continual use with much greater loads in leg prosthetics. And yes, the price of the rolls ($189 for 800 cm3) is cheaper than a commercial prosthetic...but a bit harder for a non-profit to absorb. I fully agree we could speak with MF about the issue, and in fact I've spoken to the local distributor who donated several rolls for our testing purposes.

Ideally, I'd love to get into their metal printers.....but it's hard to convince a school system to pony up >$120K when they can purchase $20K Tormach PCNC 1100s for our schools. We are also machining a lot of parts, but that seems to defeat the purpose of eNABLE when it becomes necessary to have expensive equipment to make prosthetics for donation.
Never the less, let's chat about possibilities. And let's determine an approach for MF....they are good people.

DC

David Chen Fri 16 Mar 2018

Oh, Mark 2. I was thinking Markforge v1.
I'm not sure how the e-nable funding model works, as I was under the impression that the end-user paid for the basic bill of materials? I don't think a composite hand needs to replace the ABS ones that seem to be working fine, but maybe offer it as a more expensive "sports" version for people who want any extra strength it provides (if it provides any meaningful improvements at all).

As for legs, it may be something where a steel rod with a 3D printed faring would be the ideal mix of form and function. But a composite faring would still be preferable IMO since its easier to bash your legs against something and break a normal print.

I agree that we should avoid expensive equipment if possible, but I'm not sure its possible to do a leg with consumer stuff. The load seems too much for all the off-the-shelf materials, and aside from MF and metal printers, I'm not sure of any other industrial printers that can do it either. But if its a need a lot of kids have, I think we might want to expand the scope of E-nable where for some prosthetics, one couldnt just buy a 'cheap' printer and get going.

For some prosthetics, it may require a more exclusive program that recruits businesses who can put their machines to work during downtime. Aside from good press, it would benefit MF since the additional wear and tear should result in more money spent on replacement heads, plates, maintenance, etc. But at the end of the day, I think e-nable should be able to adapt to the end user and provide an accessible (even if not always free/near-free) prosthetic no matter how it gets made.

JS

Jon Schull Tue 20 Mar 2018

re the e-NABLE funding model:
Typically the recipient does not pay for the device or materials.

(re "wiretapping": bizzare autocorrect error. now manually corrected)

RB

Rich B Fri 16 Mar 2018

Hi David:
Why don't you pick out a hand design that is approved and scaled to a potential user. I would like to suggest you contact Peter Binkley to see if his son would like a carbon composite hand. I think Peter's experience would be beneficial.

I for one would like to be kept in the loop for future printing with the modified protocols for our Ultimaker 2+.

Rich

Rich Brown,D.C. President Handling The Future, Inc. C (914) 475-2863

Handling the Future, Inc. Club (HTF) is a group of senior volunteers from diverse professional
backgrounds who, as a group of individuals from Valencia Lakes, Tampa, are affiliated as a chapter with and assist www.e-NABLE.org ( http://www.e-NABLE.org ), www. EnablingtheFuture.org. HTF’s purpose is to educate and achieve the three dimensional (3D) printing quality that provides a potential solution to those who need our assistance.

Handling the Future, Inc. Is a registered Florida Non-Profit Corporation and a 501 C 3 Charity.

DC

David Chen Fri 16 Mar 2018

Thanks Rich.
I'll contact Peter and have his son pick out a design if hes interested. But if going composite on all/some components can result in a significantly more durable and/or stronger hand, then it may be a good option for those who want to play sports or have grown up a bit. Do kids continue to use 3d printed hands once they reach teen years? I noticed all the photos tend to involve much younger kids (4-8yo it looks like).

DC

David Chen Tue 20 Mar 2018

Something else that comes to mind is the importance chemical and thermal resistance. ABS and PLA are both very susceptible to solvents, and PLA has an extremely low glass transition temperature of only 60C. So for housecleaning or cooking, I wonder if the standard ABS/PLA hands have any issues with either. From what I can gather, the other components (screws, cords, rubber bands) are probably ok in this department, so only the plastic seems to be susceptible. This would be a good application of carbon nylon, which has a very high thermal deflection of 145C and is chemically resistant. It could allow for a wider range of ADL's.

DC

David Chen Tue 20 Mar 2018

https://imgur.com/a/O7lww
After talking with Andrew Delisle, it seems like the Ody 2.0 is the ideal hand to make if I were attempting to make one of exceptional strength and durability. I've attached images of how I sliced each part and it looks like the total print material use will be ~$110. I'm guessing the leather, fasteners, buckle, and stuff probably won't be more than $10-20, so total BOM is likely ~$125.

Since I have nobody in particular I'm fitting this to, I used a 150% scale and it is the left hand. My hope is to have a PLA/ABS version to do strength test comparisons with. If someone has one close to 150% scale, that would be great. The improvements I'm hoping to achieve over a normal PLA/ABS version is increased durability, strength, and chemical/thermal resistance for maximum versatility in performing ADL's including strength training with elastic bands and food preparation in proximity to boiling water and heat. Participation in more contact-heavy sports may also be possible given the impact resistance of the carbon nylon.

Drawbacks aside from the higher pricetag is the lack of color selection: carbon nylon comes only in black. Range of improvement is also unknown and need to be measured. It requires a more specific printer to print, though you can print carbon nylon from consumer printers, just not the reinforcements. Only carbon nylon would still have the benefits of being more durable and chemically/thermal resistant, though would likely not have the stiffness. Estimated price for that would be about $25-30 in filament. I actually do have a spool of it (hopefully its still good) and may be able to print a plain CarbonX version to compare it to as well if I can borrow someone else's open source printer.

The ideal user would either be someone who is done growing (adult/late teen) or perhaps a younger child who is more active / rambunctious. I would like to submit this for voting if the community thinks that some users will need the theoretically higher durability and strength.

PG

Patrick Geary Wed 21 Mar 2018

Hi David,

I'm very interested in what you are suggesting. Can you please help me find more information on this kind of manufacturing process.

Kind Regards
Patrick

DC

David Chen Wed 21 Mar 2018

Composite printing basically uses a dual-extruder system, where the 2nd extruder uses a thin continuous string of either fiberglass, carbon fiber, or kevlar (depending on the printer model). Its heated up to about 230C and used as part of the in-fill, and is laid and "smushed" into the base material so that when everything is complete, it acts almost like steel rebar on the inside of concrete. There is a cutter that cuts the filament once enough is extruded. Carbon nylon is standard nylon with carbon ground up and mixed with the formulation. Normal carbon is very malleable, almost like rubber, but carbon nylon parts feel like ABS parts in stiffness. They are quite abrasion resistant and sand poorly, are difficult to paint since nothing sticks well to nylon, and are more expensive than ABS.

You can get generic carbon nylon for open source printers or those that dont lock you to the company's materials, though the quality of the prints from Markforge printers is truly a step above any FDM part I've ever seen. However nobody else to my knowledge does composite 3d printing. The parts produced are incredibly strong, and it was this feature alone that made my partners and I decide to buy this printer. It saves us the trouble of CNCing aluminum parts a lot of the time.

https://www.3ders.org/articles/20161117-markforged-releases-3500-onyx-one-3d-printer-for-carbon-fiber-parts.html

DC

David Chen started a proposal Wed 21 Mar 2018

Printing Filament Comparison (PLA/ABS vs Carbon Nylon vs Reinforced Carbon Nylon). Closed Sat 7 Apr 2018

Most hands are made out of PLA and/or ABS, which though affordable and easy to source, have physical limitations such as low temperature tolerance, chemical sensitivity, and brittleness. It is still the ideal material for growing children as it is extremely low cost when buying generic, is widely available, and replacing it either due to outgrowing the hand or breaking it is financially insignificant. It also comes in a wide range of colors, allowing for more decorative options which kids in particular like to have.

For adults, late teens, or just extremely active kids, it may not be the best material for the aforementioned reasons. Carbon infused nylon may be more applicable since it has a much higher temperature tolerance, is chemically resistant, is very hard to break (usually just stretches and deforms), and with some printers, can be internally reinforced with fiberglass or carbon fiber filament. A composite reinforced hand may have significantly less flex and thus allow greater user strength and wider range of ADL’s such as cooking, cleaning, weight training, and sports. The drawback is mainly in the cost, with a 500g spool of 3DXTech CarbonX costing $46.00 from Matterhackers, which is about 4x the price of ABS and PLA. A reinforced hand would be even more expensive, as the only printers capable are from Markforged, which uses proprietary carbon nylon called Onyx that costs $200 a kg, and $230 for 150cm3 of fiberglass. For comparison, an Ody 2.0 hand scaled to 150% would cost about $5 in ABS, $20 in generic CarbonX, $60 in Onyx, and $125 if reinforced with fiberglass.

For most kids, this is both too expensive and probably unnecessary. But for individuals who are fully grown or participates in more rigorous activities, this may be a bargain since they will not be growing out of it, and can use it for the entirety of its longer life. $125 is still a bargain for a young professional if it means not having to replace it for years to come. However since much of these benefits are theoretical at this juncture, I would like to conduct tests comparing each printing method. I have a Markforge printer that can print the reinforced hand, and I have a spool of CarbonX that can be used for the carbon-nylon-only hand. I’m sure I can find someone local to do the ABS one, or perhaps someone here can print it and ship it to me. The tests I am interested in conducting are:

1) Strength – weight limit of how much a hand can hold when holding a weight with the palm up to simulate flexion. If the hand fails and breaks, the characteristics of the break will indicate any possible dangers during activity. PLA will likely be the weakest, but both PLA and ABS will likely break leaving sharp edges that could cause further injury if exposed during sports or physical exercise. Carbon nylon will likely deform and stretch but not snap entirely, so lacerations from sharp edges is unlikely.

2) Chemical Resistance – A variety of household cleaning chemicals and common solvents will be sprayed onto the hand using a spray bottle, then wiped off with a paper towel and/or rinsed under water. Signs of discoloration and physical corrosion will indicate chemical sensitivity and limitations in the types of activities one should avoid. PLA will likely be the most sensitive, with ABS being more resistant, and carbon nylon being the most resistant.

3) Thermal resistance & durability – Each hand will have the leather and straps removed, and washed in the dishwasher on normal cycle. Whether it deforms or breaks apart will indicate weakness to high heat and/or agitation. PLA will likely deform and fall apart entirely, though ABS may also weaken and parts may detach. Carbon nylon may or may not survive without any obvious damage.

Resources needed: Grant of $200 should cover the materials to make all 4 hands, especially if another volunteer can provide the ABS/PLA prints. Results will be documented via video, photographs, and written observations.

Time needed: Likely a month at most as it would take a week or two to procure and build all 4 hands.

Any hands that survive the testing and appears to be functional and safe may be sent to an appropriate candidate for personal use.

Agree - 4
Abstain - 1
Disagree - 2
Block - 0
7 people have voted (8%)
SM

Skip Meetze
Disagree
Thu 22 Mar 2018

(1) reinforced nylon has special design constraints, (2) the increased strength is not justified for our upper limb devices and (3) it is difficult to get a cosmetically satisfactory hand with the reinforced nylon.

AJ

Asad Jabbar
Agree
Tue 27 Mar 2018

Interested to know about the test. It will be a good test to follow. but if the test passes. how can the price be lowered?

DD

Doc Davies
Agree
Tue 27 Mar 2018

DD

Doc Davies
Agree
Tue 27 Mar 2018

This work is not only important to produce the type of durable device needed for more demanding activities by our users such as sporting or strenuous activities and to start the development and research of lower limb devices.

RH

Richard Hodgdon
Abstain
Tue 27 Mar 2018

The material is certainly stronger, but most of our volunteers would probably not be able to make use of it. I expect you'll find good results, but will we be able to make them accessible to most of our volunteers to offer?

QM

Quinn Morley
Disagree
Tue 27 Mar 2018

JS

Jack Sutcliffe
Agree
Wed 4 Apr 2018

RB

Rich B
Agree
Thu 5 Apr 2018

DD

Doc Davies Wed 21 Mar 2018

Great summery.....

SM

Skip Meetze Thu 22 Mar 2018

We experimented with devices made with Markforged printers using fiberglass reinforced and carbon reinforced nylon. We abandoned the approach because (1) reinforced nylon has special design constraints that take special knowledge to be successful, (2) the increased strength compared to the easier printing in unreinforced nylon using ordinary FDM printers is not justified for our upper limb devices and (3) it is difficult to get a cosmetically satisfactory hand with the reinforced nylon. Also, the Ody Hand was a great exploration of Peter Binkley’s push-pull tendon technology, but it is not widely used in our community. I encourage you to get involved with fabricating proven e-NABLE devices to find where the properties of reinforced nylon might have value.

DC

David Chen Thu 22 Mar 2018

Thank you for the info. I knew someone had to have had the same idea at some point. Which models are widely used? For 'cosmetically satisfactory', do you mean color selection?

SM

Skip Meetze Thu 22 Mar 2018

The Gripper https://plus.google.com/u/0/+SkipMeetze/posts/LmEnes8b5Vu is easy to fabricate, and even though it is still experimental it might be a good place for you to start. Nylon (printed with SLS or FDM) can be dyed post printing, but I think you are stuck with the uncolored or motley appearance with reinforced nylon.

DD

Doc Davies Thu 22 Mar 2018

I read Skip Meetze's comments with a bit of concern.

Let me respond to the individual points for some clarity...

1) reinforced nylon has special design constraints that take special
knowledge to be successful,

Actually, we have not found constraints but rather opportunities. By that, I mean that with a little reasoning, one can make better use

of the integrated strength of the filament in the part. The printer itself functions almost identically to normal FDM printers. The only major difference is

choosing to either use (composite construction), or not use (just normal carbon reinforced nylon) Carbon Fiber, Fiberglass or Kevlar reinforcement. And then

just determining how the material should be added to the print. We've had success in both these areas.

We've had elementary and middle school students design parts for demanding situations like quadcopters, skateboards or school engineering projects

with little additional training. In fact, one elementary student successfully used TinkerCAD to make a viable design which proved functional in

a very rugged application.

The machine itself is more "industrialized" and rugged in student work environments (and trust me our kids tax our printers). Of course for the price....it better

be! But we chose it to supplement our Pre-Engineering courses at one of our high schools....and have had two engineering college representatives

commend us for teaching "potential" college students "state of the art" technology.

My goal, wish, dream, scheme.....is to get a metal 3D printer to further develop the students abilities, exposure and experience. We are currently working

with the College of William and Mary and Newport News Shipbuilding to obtain prototype devices for testing.

That folks, would open up an entirely new pathway for our projects.

(2) the increased strength compared to the
easier printing in unreinforced nylon using ordinary FDM printers is not
justified for our upper limb devices.

Yes, this may normally be true. But we have two kids, one who plays basketball, and one baseball who routinely break the current parts we make them with

standard FDM printing. We are currently making comparable reinforced parts for destructive testing before producing them in quantity for the kids. I'll keep

you informed as to how that experiment is progressing.

As for lower limb devices......after the testing we've done.....I don't know how you will produce functional parts without this approach.

(3) it is difficult to get a
cosmetically satisfactory hand with the reinforced nylon.

Well you've got me here in one sense......to paraphrase......"you can have a device in any color, as long as it's black"....

But that having been said, general consensus among our makers and users...is that the parts printed with reinforced nylon are of a smoother

surface texture and artifact free nature than normal FDM parts.

Now no one should have any illusions as to the increased COST of these types of parts.....the printer alone is ~$15K...and filament and reinforcing

material is expensive. But the parts are incredibly durable and strong. And we may find that the entire device does not need to be constructed using

these parts, but only critical sections. I believe that's an area we should examine closely.

In summary, I feel we should continue this line of experimentation and determine just how parts printed in this manner can supplement and extend

our current offerings and potential new designs.

Since I realize these comments may generate some, ah....discussion...please feel free to comment on this message or contact me personally

to discuss your opinions, observations or suggestions.

Doc

Bruce "Doc" Davies, Ph.D.

Co-Director

Chesterfield County Makerspace

docdavies2005@gmail.com

DC

David Chen Thu 22 Mar 2018

That's my thinking as well:

1) Not needed for everyone, but few better options are out there for select individuals

2) High quality black finish vs low quality colorful finish - I think older kids and adults would prefer the former.

3) Lower limbs - not sure how else you could possibly design for this without going to metal.

4) Price - Onyx Pro is about $7500 with tax/shipping, so definitely expensive, but I think a well designed corporate partnership program could fulfill the smaller volume of parts needed. Unless you absolutely need carbon fiber or kevlar for some reason, you don't need the $15000 Mark 2. And if even just a plain carbon nylon print is more durable, then thats a cheaper alternative that can be printed on a variety of printers.

5) Selective reinforcement - If key components are ID'ed so not every part needs to be reinforced, it would help cut costs. Parts could also be further modified to facilitate fiber routing to provide better strength, and print orientation could be adjusted as well.

If there are tangible benefits to be had, I think having the option would be appreciated. The main concern would be funding and cost, and if E-nable insists on making everything at no cost to the user, then you might have people requesting reinforced hands exclusively as it costs them nothing more to do so. But I think such supply/demand problems can be addressed should they appear, whereas allowing some users to participate in a wider range of activities is a benefit too good to keep buried. For someone in my profession (industrial design), I can think of no better material since I get exposed to solvents and high heat all the time in the shop.

DC

David Chen Thu 22 Mar 2018

If your tests do show that this is something worth offering, I'd glady offer my printer up to make parts when its not in use.

DC

David Chen Tue 27 Mar 2018

A standard Carbon Nylon hand does not need a markforge or its expensive Onyx material. One can print with CarbonX from 3DXTech on most printers that are not locked to a proprietary material. I'm currently retrofitting a Stratasys 768 for this purpose. Carbon X is not particularly cheap at $190/ 2kgs, but its significantly lower than Onyx at $220/kg It may even be possible to run it on the markforge with their new Gen2 formulation, and I'm getting a spool to experiment with it. If it works, then the fiberglass reinforced version will drop in price as well. Its not going to become $30 unless the filament makers bring the price down that low, which may happen over time but I don't imagine it will ever match dirt cheap ABS/PLA.

Given whats been discussed, I do think lower limbs should be explored, at least for kids. I don't think it would ever be $30 unless the printing is exclusively for the faring. But its plausible that a 3D printed "cup" can be done out of a elastomer like Ninjaflex, and have it act as the cushion material when bridged to a carbon nylon brace that is connected to a steel rod that connects to the foot or something to that effect. It would definitely be better to use carbon nylon in this application since its much easier to bang your leg accidentally on a table leg or something than your hand.

But regarding the cost, I think trying to keep everything near-free to make would significantly limit the potential reach of E-nable not to mention limb development. When there are no other options whatsoever, a $200 leg/foot is still leagues more accessible to a $2000-$20,000 one. Is it not better to provide the option to people than to not even have it due to some convention?

DC

David Chen Tue 27 Mar 2018

DC

David Chen Tue 27 Mar 2018

Something else that can be done to reduce the cost is to create a go-fund-me template that people can use, and a media press kit that they can then send to a local publication like a newspaper that can be ran on a weekly basis. Kind of like the missing people "have you seen me?" milk carton campaign. If all they need to do is raise $1-200, I think that would be pretty easy.

DD

Doc Davies Mon 2 Apr 2018

David, why don't we continue this conversation. I have some funding from a foundation that I can use to purchase a couple of rolls of filament for you machine and mine. We can continue testing and work with some other folks who have shown interest in this approach. If you can provide a separate email address, I'll send you mine. The good news is, I've made contact with the local Markforged distributor and through him a gentleman AT Markforged that would be interested in discussing our ideas.

DC

David Chen Thu 5 Apr 2018

My personal email address is dukenukem117 at gmail (pretty much everything with David Chen was taken, lol). When I was slicing the Ody, there were many times where I wish a certain feature was larger or expanded in a certain direction so I can pack the fiber for best results. I think if possible, modifying one of the hands to best fit the printer makes more sense than overpacking an existing hand and hoping that its reinforced in the right areas. Especially with the pins, which would be so much better if they were made thick enough to fill with fiber.

I think a 4-finger hand may actually be a good compromise in looking more natural and less like a claw, while not being overly complicated and having tiny features like a 5-finger. I'm also thinking about thermoplastic inserts (I have a bunch of big ones) to replace having a nut on the backside and thus reduce the risk of losing something.

Regarding the kid(s) that were breaking the standard ABS/PLA hands, what areas seem most prone to breaking?

P

Patrick Wed 4 Apr 2018

I am interested. Before I vote, can you provide to me and if the group wants as well...the line item breakdown? (not speculative, but actually purchase order. By speculative I mean in terms of cost, not your knowledge on the matter. Sounds like you did your homework) I like to see how things are being spent and the comment "especially if someone..." leads me to believe you may need to rely on unconfirmed resources. As such, if you can provide line-item for the $200 (or even more if needed), I would rather you have enough for the project by having it completely "line-itemed". Sorry I'm addicted to...that won't sound good.

DC

David Chen Thu 5 Apr 2018

https://imgur.com/a/O7lww
Their proprietary slicer actually gives you a pretty accurate cost estimate for the raw material on the top left, underneath the cm3 required. However upon thinking about it some more, I think over stuffing an existing design is just the laziest way to check the box. For best results and highest likelihood of long term viability, looking into redesigning the way a hand goes together that best utilizes the fiber properties would be better. When I have some time I'll take a look at the available files for one of the hands (maybe the ody just for its simplicity) to see if I can manipulate it in the CAD software I'm trained on.

P

Patrick Thu 5 Apr 2018

P

Patrick Thu 5 Apr 2018

I am not asking how I can go research your project, I am asking can you do a price breakdown of the project you are requesting funds for. I am eager to learn what you have posted, but I am asking for "line-item pricing"

P

Patrick Fri 6 Apr 2018

Check out how they formatted this proposal. That is like all I would want to see as well. Things such as "hours", "how much for those hours". Just formatted like that so I can look and go "ahhhhh I see." I am down to continue discussing off thread too! Looks good so far. https://www.loomio.org/p/FMdkc8ur?utm_campaign=poll_mailer&utm_medium=email&utm_source=outcome_created

DC

David Chen Fri 6 Apr 2018

Let me review the possibility of designing a 4-finger hand that's designed to be reinforced and then submit a new proposal based on that when the time comes. How do I retract this proposal for now?

P

Patrick Sun 8 Apr 2018

You can always submit more than 1 proposal. Don't give up on one idea unless you have tested that you believe it not to be effective. Not trying to "strike any ideas down", just trying to explain for you to "be economical" in drafting these as that will surely acquire my vote! I am willing to take it off-thread. pfcarreiro @ g mail

DD

Doc Davies Wed 4 Apr 2018

That should go to David Chen