The article in Ski made me think. I am an Engineering student at Montana Tech and needed to come up with a project to design for class. What better than a press to make my own skis. I do have some questions right away. Is the press shaping the ski, or just providing the required pressure to allow the components to integrate?
Looks like I posted in the wrong spot. guess i ski green circles
New to SkiBuilders and looking to build a hydraulic skipress
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
einan,
welcome to SkiBuilders. Montana Tech is a nice school and great place to be.
the ski press is designed to uniformly press the ski materials (with epoxy) against a mold. the vertical profile of the mold follows that of a ski, so essentially the press is shaping the ski. when the expoxy cures, the ski materials take the shape of a ski, i.e., camber and tip/tail curvature.
are you trying to build a pneumatic or hydraulic press? pneumatic might be easier. if you want to add some analysis and "engineering design" into your project, consider the following: do an analysis of the stresses and deformation of your design based different pressures. a finite element analysis (FEA) would be nice, for example using the FEA package in Solidworks. that way you can justify your design, like the size of the beams used in the press frame, etc. you could also build a nice heated presss and design the feedback control system (this is more complicated). you can justify the controller design by finding a model of the heated-press system (most likely 1st-order with a relatively long time constant) and then use Matlab to simulate the response of a PID controller. adding a few thermocouple wires and measuring the response you can compare the simulation with the measured response to note any differences. from there you can optimize your heated press.
there are other things you could consider in your design project.
good luck.
welcome to SkiBuilders. Montana Tech is a nice school and great place to be.
the ski press is designed to uniformly press the ski materials (with epoxy) against a mold. the vertical profile of the mold follows that of a ski, so essentially the press is shaping the ski. when the expoxy cures, the ski materials take the shape of a ski, i.e., camber and tip/tail curvature.
are you trying to build a pneumatic or hydraulic press? pneumatic might be easier. if you want to add some analysis and "engineering design" into your project, consider the following: do an analysis of the stresses and deformation of your design based different pressures. a finite element analysis (FEA) would be nice, for example using the FEA package in Solidworks. that way you can justify your design, like the size of the beams used in the press frame, etc. you could also build a nice heated presss and design the feedback control system (this is more complicated). you can justify the controller design by finding a model of the heated-press system (most likely 1st-order with a relatively long time constant) and then use Matlab to simulate the response of a PID controller. adding a few thermocouple wires and measuring the response you can compare the simulation with the measured response to note any differences. from there you can optimize your heated press.
there are other things you could consider in your design project.
good luck.
einan,
I hope you do build a hydraulic press. Pnuematic presses tend to be noisy due to the compressor used. I've worked with light hydraulic platten presses that used a small 110/220 motor to keep the pressure up. and they were quiter, by far.
One thing you might consider is desinging, building and testing an electric motor driven hydraulic press for the home builder. (possibly look at one in 110v and one in 220v, as most of us don't run 220v into our garages). A press that can produce an even 10 to 80 psi and which has a short cycle time (time it takes to open and close to place another mold in). If you come up with a real workable model, there might be a market for amatuers and small manufactures.
If you are a good scrounger, a good industry quality press should not cost more than a couple thousand US to build (exlucing any labor for a machinist or welder if you employ one). Compare that to 15,000us to 45,000us for a factory built machine.
If you are very creative and have a bit of luck, you might find a way to build it for free.
Regards,
J
I hope you do build a hydraulic press. Pnuematic presses tend to be noisy due to the compressor used. I've worked with light hydraulic platten presses that used a small 110/220 motor to keep the pressure up. and they were quiter, by far.
One thing you might consider is desinging, building and testing an electric motor driven hydraulic press for the home builder. (possibly look at one in 110v and one in 220v, as most of us don't run 220v into our garages). A press that can produce an even 10 to 80 psi and which has a short cycle time (time it takes to open and close to place another mold in). If you come up with a real workable model, there might be a market for amatuers and small manufactures.
If you are a good scrounger, a good industry quality press should not cost more than a couple thousand US to build (exlucing any labor for a machinist or welder if you employ one). Compare that to 15,000us to 45,000us for a factory built machine.
If you are very creative and have a bit of luck, you might find a way to build it for free.
Regards,
J
Hi, if you build your bladder of good quality your compressor will only be running when inflating the bladder and afterwards mayb once per hour.justin56 wrote:einan,
I hope you do build a hydraulic press. Pnuematic presses tend to be noisy due to the compressor used..... a couple thousand US
Also you say a couple thousand US. Are you going to start a prof. ski building shop?
Buuk
Make things as simple as possible, but not too simple
Buuk,
Consider that you can spend around the same price for high-end skis retail over a few seasons in one's lifetime, it looks reasonble.
Currenty, around $2000us can get the amatuer into a high performence press without the need for special sourcing. A good scrounger can probably built one for next to free.
My current press I am building will cost me about $600us. Most of that was for heater strips, pneumatic fittings and steel odds and ends. Most of my steel I found for free or I traded 1/2 plate steel for. This will be the ninth press I've worked on.
As for compressors and noise, I've worked around them most of my working life and I say if you can get away from using them, you're better off. Most owners of compressor don't realize the sound levels they can produce and even for short term exposures its their use over time that can be damaging. Most home shop ownsers use them in enclosed spaces...which is not good.
Of course, if you're press design uses an air bladder directly against the mold then hydraulic would not be possible.
Hydraulic presses usually require a male and female formblock.
Consider that you can spend around the same price for high-end skis retail over a few seasons in one's lifetime, it looks reasonble.
Currenty, around $2000us can get the amatuer into a high performence press without the need for special sourcing. A good scrounger can probably built one for next to free.
My current press I am building will cost me about $600us. Most of that was for heater strips, pneumatic fittings and steel odds and ends. Most of my steel I found for free or I traded 1/2 plate steel for. This will be the ninth press I've worked on.
As for compressors and noise, I've worked around them most of my working life and I say if you can get away from using them, you're better off. Most owners of compressor don't realize the sound levels they can produce and even for short term exposures its their use over time that can be damaging. Most home shop ownsers use them in enclosed spaces...which is not good.
Of course, if you're press design uses an air bladder directly against the mold then hydraulic would not be possible.
Hydraulic presses usually require a male and female formblock.
Geoff,
Let see, how shall I put this delicately and legally...
"Picture of presses I've built or worked-on while employed by third party interests would not be available for public viewing at this time."
When I finish my current press I will need to check with my lawyer to see if I can publish them--actually, that's if I survive the initial testing....
In the interim, I can comment on any questions and offer advice. I'm looking for same on here, as well.
I can say that many of the presses that have been shown on this forum are very close to what industrial laminators would use. The only differences tend to be in weight...however, that is the clincher. Greater pressures require better resistsance to deflection...which for the garage builder usually means huge amounts of weight and exponential cost.
Also, the type of molding systems used dictates the design of the press and its systems. So, there is no single absolute way to build a good press. There is, however, an optimal way for a given press/mold system--and that is the one that meets the need of the operator.
The Physics involved doesn't change regardless of how much you spend or what materials you use. The solution to any given problem can be solved many ways.
That being said, my advice to any home builder is to question the way things are done in any industry. If you can, learn from their mistakes, but realize you have the gift of time and ingenuity on your side. Often times the way industry approaches produciton is not the best way nor the cheapest.
Same goes for materials.
Regards,
-J
Let see, how shall I put this delicately and legally...
"Picture of presses I've built or worked-on while employed by third party interests would not be available for public viewing at this time."
When I finish my current press I will need to check with my lawyer to see if I can publish them--actually, that's if I survive the initial testing....
In the interim, I can comment on any questions and offer advice. I'm looking for same on here, as well.
I can say that many of the presses that have been shown on this forum are very close to what industrial laminators would use. The only differences tend to be in weight...however, that is the clincher. Greater pressures require better resistsance to deflection...which for the garage builder usually means huge amounts of weight and exponential cost.
Also, the type of molding systems used dictates the design of the press and its systems. So, there is no single absolute way to build a good press. There is, however, an optimal way for a given press/mold system--and that is the one that meets the need of the operator.
The Physics involved doesn't change regardless of how much you spend or what materials you use. The solution to any given problem can be solved many ways.
That being said, my advice to any home builder is to question the way things are done in any industry. If you can, learn from their mistakes, but realize you have the gift of time and ingenuity on your side. Often times the way industry approaches produciton is not the best way nor the cheapest.
Same goes for materials.
Regards,
-J
I've always been wondering what the advantage coulde be of an autoclave.
I saw some company using autoclaves for laminates but I think an autoclave doesn't press ass much excess resin out of the lamination as such pneumatic or hydraulic presses. Or am I wrong?
We don't talk about costs in this case but that's what I've been wondering.
Geoff
I saw some company using autoclaves for laminates but I think an autoclave doesn't press ass much excess resin out of the lamination as such pneumatic or hydraulic presses. Or am I wrong?
We don't talk about costs in this case but that's what I've been wondering.
Geoff
i am gungho all for the autoclave (thats my ultimate goal for presses). My best price yet will be capable over 100psi for about $1K. This presses more resin out and more evenly than a vertical press (at the same psi) for a number of reasons. First of all in a press your 100 psi would not be applied over the entire surface of your board or ski...it would be applied only to the horizontal surface (fine for sandwich boards, not so good for capped)...also it only applies to a narrower area when using a cattrack (width of the bladder depending how compressed it is). Autoclaves press at all angles evenly, equally high pressures over larger areas (for overall more force). Aerospace companies even use steam based autoclaves or hydroclaves for safer, higher pressures that can heat cure with more efficient heat transfer.
I have tried to make autoclaves with every ghetto method you can imagine (the inner tube method was a classic
)...but bottom line is you really cant skimp on this, its either Steel pipe for 2K, HDPE pipe for 1K, or discharge hose (30psi) for about 300 bucks.
I have tried to make autoclaves with every ghetto method you can imagine (the inner tube method was a classic
)...but bottom line is you really cant skimp on this, its either Steel pipe for 2K, HDPE pipe for 1K, or discharge hose (30psi) for about 300 bucks.Geoff,
The problem I've seen with technolgy like 'autoclaves' is that it came into the ski and later snowboard manufacturing industies by way of the "aircraft industry" --via large corporations that purchased ski manufactures. They probably figured they had this expensive "thing" sitting idle for x hours per day, why not use it to make skis--time is money, after all.
The technology did not come into the industry to answer any specific need or solve any major problem, so its relative value as a building method has always been in debate. It was used by a few ski companies in the past as a marketing point.
Most ski manufactures are not using the types of materials and resine systems that truly benefit from an autoclave method--so it tends to be a moot point if not a detriment to the actual quality fo the product.
I've never seen a production model ski that showned any superiority from it being born in an autoclave.
The best performaing skis I've seen (and the lighest) were made using a simple pnuematic press, fiberglass (no graphite, no carbon no etc.) and a plastic mold. Not too high tech there.
I guess the old phrase "don't believe the hype" pertains well to the autoclave mistique.
The problem I've seen with technolgy like 'autoclaves' is that it came into the ski and later snowboard manufacturing industies by way of the "aircraft industry" --via large corporations that purchased ski manufactures. They probably figured they had this expensive "thing" sitting idle for x hours per day, why not use it to make skis--time is money, after all.
The technology did not come into the industry to answer any specific need or solve any major problem, so its relative value as a building method has always been in debate. It was used by a few ski companies in the past as a marketing point.
Most ski manufactures are not using the types of materials and resine systems that truly benefit from an autoclave method--so it tends to be a moot point if not a detriment to the actual quality fo the product.
I've never seen a production model ski that showned any superiority from it being born in an autoclave.
The best performaing skis I've seen (and the lighest) were made using a simple pnuematic press, fiberglass (no graphite, no carbon no etc.) and a plastic mold. Not too high tech there.
I guess the old phrase "don't believe the hype" pertains well to the autoclave mistique.
Geoff,
It depends upon the autoclave system.
Some use vacuum to actually pull the resin through the object--but this requires a very good understanding of the medium(expoxy) used otherwise its a hit into the dark.
To tell you the truth, most ski companies are not experts in this area--so they rely upon their resin and component suppliers. In a sense they can fall victim to the "propaganda" their suppliers tell them—after all, mr resin seller has to make a living too.
Unfortunately, in most of the sporting goods industry there is this myth (propagated by marketing departments) that what's good for the aerospace industry is good for inanimate objects that are meant merely for sport! Sometimes they are, but mostly they don’t do anything for us but maybe cause some pain in rethinking and rework.
Name the most recent "buzzword" in sporting goods marketing, and you can bet that there is something more (actually less in a structural sense) going on than is suggested. Nothing can replace your own development and testing! Don't believe the hype!
An example of this was the “graphite” craze of a few years ago. All a manufacturer needed to do for legal compliance in many countries was to have the layup-person use a salt shaker full of graphite to “lightly dust” the e-glass or uni-glass ski they were building. The costumer never knew and the law never required it to be defined.
Ski companies capitalized on this ignorance, as most buyers would assume that the glass somehow had strands of graphite in them. So, a ski or board with this label must be better than one with out, right? The graphite within the finished product had no structural impact what so ever, more often than not.
Most recently it has been the carbon craze. All I have to say about that is spend the money (it is very expensive for the homebuilder to do good R & D at current prices), build a few and you’ll see for yourself.
There is more than one reason why we had a shuttle disaster and it wasn’t just because a guy spit into his epoxy bucket. Carbon fiber is one of the most prevelent referenced "miracle fibers" that most in the composites industry really don't understand but would be the first to laud its abilities.
However, if you have the money, an autoclave is still is a worth while pursuit. One should never give up any technology. One might put it aside, but one should always come back to it regardless if it works or not. You may have missed something the first time round.
At this point in time I'm not convinced that an autoclave gives any advantage in building skis--maybe just in marketing them.
Oh, and something else, when eveness of pressure and resine/expoxy flow is discussed it must be assumed that all other variables such as materials, temp and pressure are known comodities. Simply having an even epoxy flow is not nessecarily a good thing. In some lamination applicaitons you want the expoxy to flow more slowly to saturate certain types of materials and flow more readily to others. A skilled wet layup technicain can do this with experience. It would be difficult to desing this into a pressure system.
It depends upon the autoclave system.
Some use vacuum to actually pull the resin through the object--but this requires a very good understanding of the medium(expoxy) used otherwise its a hit into the dark.
To tell you the truth, most ski companies are not experts in this area--so they rely upon their resin and component suppliers. In a sense they can fall victim to the "propaganda" their suppliers tell them—after all, mr resin seller has to make a living too.
Unfortunately, in most of the sporting goods industry there is this myth (propagated by marketing departments) that what's good for the aerospace industry is good for inanimate objects that are meant merely for sport! Sometimes they are, but mostly they don’t do anything for us but maybe cause some pain in rethinking and rework.
Name the most recent "buzzword" in sporting goods marketing, and you can bet that there is something more (actually less in a structural sense) going on than is suggested. Nothing can replace your own development and testing! Don't believe the hype!
An example of this was the “graphite” craze of a few years ago. All a manufacturer needed to do for legal compliance in many countries was to have the layup-person use a salt shaker full of graphite to “lightly dust” the e-glass or uni-glass ski they were building. The costumer never knew and the law never required it to be defined.
Ski companies capitalized on this ignorance, as most buyers would assume that the glass somehow had strands of graphite in them. So, a ski or board with this label must be better than one with out, right? The graphite within the finished product had no structural impact what so ever, more often than not.
Most recently it has been the carbon craze. All I have to say about that is spend the money (it is very expensive for the homebuilder to do good R & D at current prices), build a few and you’ll see for yourself.
There is more than one reason why we had a shuttle disaster and it wasn’t just because a guy spit into his epoxy bucket. Carbon fiber is one of the most prevelent referenced "miracle fibers" that most in the composites industry really don't understand but would be the first to laud its abilities.
However, if you have the money, an autoclave is still is a worth while pursuit. One should never give up any technology. One might put it aside, but one should always come back to it regardless if it works or not. You may have missed something the first time round.
At this point in time I'm not convinced that an autoclave gives any advantage in building skis--maybe just in marketing them.
Oh, and something else, when eveness of pressure and resine/expoxy flow is discussed it must be assumed that all other variables such as materials, temp and pressure are known comodities. Simply having an even epoxy flow is not nessecarily a good thing. In some lamination applicaitons you want the expoxy to flow more slowly to saturate certain types of materials and flow more readily to others. A skilled wet layup technicain can do this with experience. It would be difficult to desing this into a pressure system.
The reason why I'm asking is I have a good friend which offered me the possibility to use the autoclave he is working with once. But at this moment I'm not sure it will be a good choice.
I have no press at all at this moment and I don't know right now where to get my materials like the blatter and the heat blanket at this moment.
I'm living in europe and such big blatters are a rare thing in Europe.
Are you building pneumatic presses with blatters or with double molds?
Or do you build hydraulic presses?
Geoff
I have no press at all at this moment and I don't know right now where to get my materials like the blatter and the heat blanket at this moment.
I'm living in europe and such big blatters are a rare thing in Europe.
Are you building pneumatic presses with blatters or with double molds?
Or do you build hydraulic presses?
Geoff
By all means use it!!!!
It will be a great opportunity for you to see how they work. If you have access to different epoxies, you might want to try to make several different pressings. Or, you can try pressing with different weights and amounts of one type of epoxy.
If you take notes you can always try the same techniques on a pneumatic press to compare.
I'll tell you that if someone gave me access to a stretch forming press, I'd try to find a way to make skis on THAT, just to learn something about another type of press!!!!
It will be a great opportunity for you to see how they work. If you have access to different epoxies, you might want to try to make several different pressings. Or, you can try pressing with different weights and amounts of one type of epoxy.
If you take notes you can always try the same techniques on a pneumatic press to compare.
I'll tell you that if someone gave me access to a stretch forming press, I'd try to find a way to make skis on THAT, just to learn something about another type of press!!!!