Steve,

We have Universal machines here and have had for over 12 years. I don't
recognize the model you address, we have 6241's.

When we set up our design guidelines we put the added dimension to +.014"
over lead. That is a bit off of the .019" in the design guidelines you talk
about! Of course our resistors have .024" leads.

Based on what you put here, I would say I agree with you about not taking
the time. With those size leads, the body size, and the hole size over lead
dia. I don't think you have a fair shot at the deal. I would anticipate that
the body size will begin to interfere with each other after about 5 of them
get put in. Universal does a good job as far as I'm concerned but design
really needs to be adhered to, otherwise your trying to beat the system.

Programming tips (if they still apply to your version of software): 1) There
is a squeeze command that bends the leads to the center dimension minus
.010" and then 'squeezes' them the final .010" just prior to insertion
stroke. This is good for large leaded dia. components. 2) There is also the
ability to have varying heights for the bend of the component lead sit off
of the board. You could vary this dimension with each component to lessen
the effect the .103 body has on interference between components. Both of
these are in field 8 of the program line.

Another thing you need to address is the hole location. Again I do not know
the specific design guidelines you mention, but we have a hole location
specification to be within .009" true position, and I know from experience
that this can get you if your not aware of it. I suspect that the difference
in specifications relates to the difference in age of machines.

Bottom line, pay attention to the specifications UIC puts out and you will
have no problems.

Richard Hamilton
Clemar Mfg. / Rain Bird
[log in to unmask]

P.S. Watch the warp and twist if you have passthru.

> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: Tuesday, June 27, 2000 3:40 PM
> To:   [log in to unmask]
> Subject:      [TN] Auto-insertion lead-to-hole ratios...
>
> Hi All!
>
> Please forgive this basic question, but what would be the smallest
> lead-to-hole ratio in which you would attempt to auto-insert an axial part
> (with a Universal VCD 6287)?
>
> I'm fairly new in this arena, my focus has always been with SMT. But
> anyways,
> I've always heard that the holes should be .015"-.020" larger that the
> lead
> diameter. On Universal's web page they have a *.PDF through-hole design
> guide
> that says holes should be .019" +\- .003" larger than the lead.
>
> Well, we've got this board here that uses 1/2-watt resistors with .027"
> diameter leads, I got the pin gages out and measured the holes and they're
> .035"-.036". Only .008" clearance!!!
>
> Some here say I should go ahead and write the program and just try it,
> that's
> easy for them to say...this a very large board that has close to 400 axial
> parts on it, and practically all of the parts are these resistors of
> varying
> values.
>
> I'm saying that there isn't a snowballs chance in hell that the VCD is
> going
> to do even a half-way decent job, so I don't want to spend the time it
> takes
> to create this huge program. Oh another thing about the resistors, they'e
> been laid-out on .100" centers. The diameter of the bodies range from
> .103"-.107"...they're "Brick-walled" on the board with their bodies
> touching
> each other...fun stuff, huh?
>
> I'm telling them that our CS-400's are gonna be real busy for quite a
> while...
>
> So am I out to lunch or what? From you guys experience, is it wishfull
> thinking that our VCD will be able to insert these parts?
>
> -Steve Gregory-
>

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################