GALLERY 36 Руководство по эксплуатации - Страница 17

Просмотреть онлайн или скачать pdf Руководство по эксплуатации для Промышленное оборудование GALLERY 36. GALLERY 36 18 страниц. Canvas stretching machine

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Clamping Bar is lifting during stretch

Under normal operating conditions the Clamping Bar will tend to rise a little above the

top of the angle bar as the stretching pressure is increased. When the canvas is clamped

and being stretched there is a strong upward force that tends to pull the clamping bar

upward with the canvas. This is not an issue unless the bar remains in this position or

there is excessive play. If this occurs contact us.

Stretching Bar deflecting, or deflecting unevenly

This is also a normal response during a stretch. This Stretching Bar was purposely

chosen because of the amount of deflection it has, this conforms well to the rubber

extrusion. As for the uneven bar, this is more a matter of placement of the artwork. Try

position the artwork at the center of the machine and work from there, favoring one side

will result in an uneven travel but should not affect the quality of the stretch.

Canvas is not tight

How tight is tight? There have been many arguments regarding what is considered a

tight stretch. Canvas is very dynamic and is susceptible to atmospheric conditions, what

once was tight will soon be loose. Over-stretching a canvas will give the canvas memory

and is not likely to return to it's original condition. Our belief is that stretching light

giclees at 15-20 psi is more than sufficient and that heavy canvas should be no more than

30-40 psi.

Stretching Large Art

Artwork larger than 30" x 30" should probably be made with a cross-brace; this will

reduce the amount of deflection of the stretcher bar during a stretch. There is a "keystone

effect" that occurs when stretching large pieces when the plates are placed close to the

outside rails. The rails provide strength for the stretcher frame, placing the stretcher

plates away from the center causes the stretching force to be applied more to the outside

and not in the middle were it is needed. The ideal placement of the stretcher plates is half

the distance between the center and the outside rail, do this for both sides.

Tips & Tricks

Large artwork will not typically rise very much during a stretch due to the weight of the

stretcher bar. The heavier the stretcher bar the less likely it is to rise. Most operators

would tend to increase the stretching pressure above 50 psi; this will cause the canvas to

slip out of the grip of the clamp. Instead, the operator should lift the far end of the

artwork until it is approximately 3-4" above the work surface, this will permit the canvas

to stretch over the edge of the stretcher bar with less resistance. Placing a soft foam roller

or pad of cardboard under very large artwork will produce the desired effect.